The principle of a rebound is that you lead a direction, then change your mind, either half way, or right at the end, in order to come back. Of course, you never "change your mind", you plan it all along and let your partner know about it in good time. How you do that? Simple. You lead the first direction, but as soon as your partner gets it, you lead the opposite. That way, by the time she gets to the first half of the beat, she already knows where you need her to be next.
Now, suppose you want to push this further - go one direction, then back, then change your mind again. Since the direction at the start of the movement is the same as at the end of the movement, there is no point leading the opposite direction at all, because nobody is going there. If you're in a car and you lead the backward direction, but in the end still go forward, how do you call that? A break! That's what you do here, also: you break the movement.
And you can break it more than once, during one movement. The point is that, while you release the break, you need to show your partner what comes next: another break, or a continuation. You do that in a variety of ways, two being the most notable in my humble opinion:
1. the freedom you give your partner to release the energy from the break and
2. the counter-position: you achieve the break with a counter-position, but the release is also a counter-position. The acceleration pedal is a force inflicted on the car, just as the break pedal - except you usually decide to follow-up on the acceleration pedal; however, if you decide not to, to push the two pedals alternately, you achieve a series of counter-positions which are quite clear to your partner. Something like the ABS.
But let's take the trick up a notch: reach an "American" position, then lead your partner a gancho to your forward leg and try to keep her there for a second, chained, gancho; then lead her an exit to a back ocho. ;)

That's part of the beauty of being a leader, in fact. The follower lives in a blissful ignorance of the leader's plan, and on top of that, she often has plans of her own - in her own, soft yet compelling manner.
Think of it this way. You are a married, mad scientist - and one Friday morning, with dark passion thundering in your eyes, you tell your wife: "Today, I shall take over the world!!" And she replies serenely - "Certainly, dear, but first you have to walk Schmuffles; and pick up some milk on the way, will you?..."
Personally, I think it's her hand on your back which does the trick. But no matter: the point is this - each and every step you take as a leader, each plan, each dynamic needs to depend strictly on the follower's response. It's a waste and a shame when you do a splendid back sacada with double voleo, followed by two baridas on a gyro - and in the meanwhile your follower watches amused from a safe 5 feet distance, because you lost her after the second step (when she decided to do a long, passionate caresso).
You do good, as a leader, if your follower is comfortable. And mind you, that alone is a tough game of the mind. If you are lucky enough though to have a constant tango partner, then you can reduce the hard riddle to a simple matter of communication. Naturally, there is nothing simple in that either - unless you remember what I just wrote in my title.

Take a simple exercise as a base step - leader takes a right step forward on the outside (open side of the embrace), then collects feet and changes weight at the same time; leader takes a right step back then collects feet and changes weight. That's it. Do it first on the beat, then on double beat. Chain two sequences on double beat, if you feel it in the music - but always complete any single sequence at the same speed, don't break it in the middle.

It is very important for the leader to learn how to lead the start and and the end of a double beat sequence (the middle part comes more naturally). An option which is not full-heartedly endorsed by most teachers is to give the follower a lifting sensation at the start of a fast sequence and a grounding sensation at the end (or just lose the lifting sensation :P ).

Having prepared these details, here is a small brief of musicality for any regular Milonga music:

• Milonga is made up of phrases of eight beats. You can imagine a musical phrase as a text, beginning with a capital letter, and ending with a full stop. Then the next phrase tells something different. In the music, you will usually notice that different instruments in the orchestra will start or stop playing when a new phrase begins. What is important for the dance is - you want to start a sequence when a phrase starts and end a sequence when a phrase ends. You don't want a phrase to start, catching you in the middle of a sequence. It looks bad. It looks particularly bad if you are still dancing when the music stopped completely.
• Coming back to the little exercise - suppose you do it on the beat (which is called Milonga lisa). Then, you may want to make your first step (right forward as a leader) on the beats one or five of each phrase, because, as you will notice, the music places a particular accent on those beats. The typical tango orchestra has a special instrument called the bandoneon. This instrument, much like the classical accordion, plays both during compression and expansion, but it plays stronger during compression, which normally happens on beats one and five, hence the accents
• Now, suppose you do the little exercise on double beat as well (which is called Milonga doble tiempo) - and then try to go back to normal beat. You will notice that you can become "off-phase" with the previously explained idea. Depending on how many "doble tiempos" you did, you can be off phase in two ways, depending on which beat your forward step falls. If it falls on beat four, you can do a half rebound, in double time, which will put you back on the track; if it falls on beat three, you can do a second step forward, instead of the step back.
• The third possible way to dance Milonga is called Milonga con traspie (which means "stumble"). If you listen to some Milonga music, you will notice that it has an "exposition" part, at the beginning, which gives away some of the theme (and also gives time to the leaders to invite their partners on the dance floor), then there is a clear statement of the essential Milonga rhythm (In fact, a clear statement of the candombe rhythm which survived inside the common modern Milonga). This piece of music will then accompany the whole tune, so you'd better get accustomed to it. Dancing to that piece is in fact doing the Milonga con traspie. And to do it you need to start on the end of an even beat (preferably four or eight), do a syncope, then a doble tiempo (and, if you feel like it, repeat). A few words about a syncope: take one beat, split it in four, wait for three quarters of it (poised, like a tiger), then step on the last quarter. So, a traspie step would be something like: 4(step), 4+1q(wait), 4+2q(wait - tiger like attitude), 4+3q(step), 5(step), 5+1h(step), 6(step). While that is a rather sterile mathematical explanation (mind you some of these are quite useful: I make my tie knots by such a formula :D ) - catching the piece of music that gives the traspie is infinitely more important for you (hint: it's like "ta-dam tam tam, ta-dam tam tam"... and I can keep doing that :P )

(Notes from a splendid lesson by Murat Elmadağlı (Turkey) & Vera Gogoleva (Russia))

Having just returned from TangON, with a wealth of news in my head and a misplaced notebook, I'm quite likely to just rush a sum of words with minimum sense - but I'll do it anyway, counting on my faithful correspondents to help me trace their heads and tails.

• The close embrace (Pablo & Noelia) - the right arm should delimit the couple's space, so in a sense, it is the reference of the leader with respect to the environment. Therefore, it should maintain a rather rigid vertical attitude relative to the movement, instead of leaning inside and outside when the follower's position shifts or twists. The hand's place can be more or less mobile however
• Contretiempo (Chicho) - ... is a step which is either lead to the follower and not followed by the leader, or the other way around. Reading back that sentence, I conclude that 1) I like it, it's smart and 2) it looks like a philosophical egg with a tail. So, let me explain it: many times, there is a symmetry between the leader's steps and the follower's, much like a mirror. That way, the pair stays close (e.g. in straight forward movement). But the leader doesn't lead with his feet, so one should find it possible to lead a step without moving their own feet, or move their feet without actually leading anything (or leading something which is not symmetrical with their movement). While the latter is usually easy, the former is much, much more subtle.
  As an example, try the following exercise: lead a sidestep,change of weight, then another sidestep in the same direction to your partner, while doing the same thing. Easy. Now, lead the same, but skip your change of weight, simply do a forward step, to the sidestep direction, while remaining twisted towards your partner. Your step is easy, her step is equally easy, but leading it can be quite tricky. Don't use your hands. A 'mystical' explanation says use your breath instead. Lead her a slight up/down movement, which is trick for 'step and collect', because it feels the same. Keep in mind that, even when done perfectly, there's a chance she will miss it, so prepare for that.
  A more advanced exercise: start with a back ocho; on the movement to your right, play a barida to her left foot, as if you would start a sanguchito, but instead, lead her the step back, change of weight and forward, in double time, on your right side. Don't do the change of weight, rebound to your left foot instead (you can do an adorno to keep track of time ;) ), then, while she steps forward and forward again, you cross twice in double time. At the end of this sequence, you will find yourself in a good position to lead her a stop signal and do a gancho to her left foot (which, if you are smart, you won't do).
• Giro without torsion (Damian & Celine, Sebastian & Mariana) - I'll try to summarize my take on the milonga workshops in several notes. The first two points are twin: 1) there is no time for the regular steps & torsion in the milonga tempo; and 2) it's very important that you take your time to do the steps, instead of making / leading them faster than they actually are. So the steps need to be very small and you will want to lead them in close embrace, to save time on the "communication" process. You will also want to cut corners - for instance, an ocho, which is usually done by pivoting the follower, will be done faster by simply crossing (behind or forward). Similarly, a linear giro will be done by leading a back cross (push the follower slightly away then pull her back shifted over her weight foot), to indicate the direction of the first step, while pitching to the direction where you want the giro to go. That is, of course, if you have enough space on the floor to do that. Which you normally don't. So you can evolve this into a normal giro, which is circular (as the name tends to indicate), therefore needs some torsion. Still, instead of actually twisting your torso, as you might normally do, all you need in order to get the job done is to twist your hips - and only just. Arguably (imho) this can be achieved better if the leader's right hand stays fixed under the follower's right arm, instead of sliding on her back, during the twisting moves. Not very comfortable at first, but it kind of grows on you. as a neat trick, lead a giro with all steps in double time, very small steps, and perform the same steps, mirrored. If done right, this is called a 'corelita'.
• Movement (Pablo & Noelia) - a very simple, but very important note: when you move, concentrate on the foot holding the weight, not on the free foot. The movement itself comes from the horizontal push into the pivot foot, that particular force is the vector, not the free foot pointing, or the mere inertia. This helps balance a lot, and allows the leader to plan respect the paradigm of leading: lead, check, then follow (i.e. as opposed to lead, step simultaneously and hope for the best)

Tango is a social phenomenon. The ladies get to walk their new dresses around fancy parties available all week long, the gentlemen get to show off slick moves or silk embraces, there's talk, there's tension and there's feeling.
Now, where you've got society, you've got civilization - and with it a number of rules. Since the dance itself doesn't have too many rules, most of them refer to the relationship with the others, and therefore they apply to the couple rather than its parts. Since the couple itself is asymmetrical as far as responsibility goes, if it messes up, it's the leader's fault. Just like it's the driver's fault when a car crashes.
And the resemblance doesn't stop here.

1. The leader, much like the driver, has a number of tools with which to steer, accelerate or break. Each different car steers, accelerates and breaks in a slightly different manner, and you need to get accustomed to these peculiarities, in order to drive safely.By now, the ladies have probably sneered, understanding that they are being compared to cars. In my own defense, I honestly believe that most cars are smarter then their drivers, at least in what driving is concerned.
2. You drive on the right side of the road. On your right, you should always have the landscape. (In tango, this is true also for the UK).
3. There's traffic. It cannot be avoided. Still, if you are usually more careful not to scratch your car than you are not to lead your lady into a crash, then you should feel bad for a whole minute right now!
4. More crowded traffic doesn't mean a chance for more people to see how great a driver you are. It just limits your freedom to maneuver. Often, it tests your patience.
5. It's more crowded on Friday evening. 
6. There's more than one way to drive a car - and there is a number of conditions which will commonly influence your choice - such as the traffic, the lighting, the driving surface, how tired you are, how much you like your car and how comfortable driving it is, or the music you listen to. Selectively and arguably, all these apply to tango as well.
7. When you reverse, things tend to come at you from behind. So, make sure they aren't close enough to hit you.

Try this simple exercise:

1. Stand on both your feet, as you normally do when not walking.
2. Now, keeping your body straight, try to lean very slightly to your front, as much as your feet allow it without having to make a step. You should now feel your weight resting on your toes.
3. Now, lean as much as you can towards your back. Remember, your body should not bend in any way. You should now feel your entire weight on your heels.

Maintaining your axis is a very important thing when dancing tango. In fact, you should probably concentrate most of your attention in the beginning on how to step and how to pivot while keeping your wight on the right foot.
You wouldn't want to push or pull your partner and you wouldn't want him/her to feel as trying to move a door!

This is the beauty of it all when speaking about axis. You can lean on your toes and give him/her that perfect embrace he/she's been longing for and still allow your legs to have enough room in order to make the steps, the pivots and those nice adornos you've been admiring on YouTube.
Or you can simply lean towards your back to magnify your steps, to better feel the energy and put it into your best moves.

Now don't misunderstand! During a single song, you will probably switch between the two depending on where he may lead and on how she may want to shape it. The important thing is to keep in mind that between your toes and your heels is the place you want to keep your weight and your axis. Also remember that your partner has the same range to play with when it comes to his/her axis. Therefore, the most beautiful movements will probably derive from this game you are both playing.

There will be times when you will feel that you have pushed out of this range and lose your balance. Even if this is acceptable for the first few lessons, in time, you should learn to control your body as you please! "Really?" you may ask. Well, in fact, yes! After all, it is YOUR body we are speaking of and YOU of all people should be able to control it as you please. Yes, you may lose your balance. And yes, you may not be able to make that perfect pivot from the very first lesson. But that is all probably because nobody has really explained you how to do it. In your own terms.

The key to keeping your axis is the perfect balance between the energy you are receiving and the steps you are making (together with the shape you decide to give them). For example, when talking about a voleo, you can actually pinpoint the energy rising from the leader's torso, going through his arms into the follower's arms, upper body, leg and finally all the way through to her toes, giving the beautiful shape of a voleo.

What kind of exercises can you try for maintaining your axis?

Caminar - maintain at every step your toes, your torso and your forehead on the same vertical line.
Caminar with a counter balance - work in pairs. When you are walking to the front, your partner should push you to the back. You should be able to push him back and make a step in perfect balance. When you are walking to the back, your partner should push you forward. Work until you can make steps in perfect balance. You should be able to do that by finding the equilibrium between the energy of your partner's push and the energy you invest in the movement.
Pivot to the wall - take the wall as your partner and try to make 180 degrees pivots in perfect balance. At first, you will lean towards the wall to take the energy you need. In time, you should be able to let it go more and more and finally, do the pivots on your own. After that, play with the speed of the pivots and the adornos you can do.

The second installment in our series of beginner's tips for followers. Here goes:

1. Try not to swing during the dance. Don't lift that shoulder, nor any hip. Your movement should be smooth and should not unbalance your leader. Normally, the leader shouldn't swing either, but if he does, you try to keep your balance and help his.
2. The order of things is: leader's intention -> follower's step -> leader's step. Your duty as follower is to try and feel the intention and then go with it. You will wait only if the leader wants you to wait.
3. When you make your step forward, make sure that your head, your chest and the tip of your foot align on the same vertical front. Also, when you make your step back your head, your back and you the tip of your foot should be on the same vertical line. If by any chance any of them aren't in an alignment, you will most probably break the embrace, alter your posture or simply look funny - bad funny that is!
4. Think of half tempo level. When you will get accustomed to the tango beat, it may seem too slow for you and that will only get you to think at half tempo. Doing that will allow you to make any adornos you like, tap at half time and make your dance that more interesting.
5. Think at double tempo level. When your partner leads your steps on a very slow tempo (step on 2 beats), it's a perfect opportunity for you to improve your technique. Make sure you make your steps in the right assigned place on the floor, that you don't hesitate in moving your weight, that you have a perfect posture, that you continuously maintain the embrace and so on. The slow dance is the best way to test a lot of your skills.
6. Ocho is a very useful trick that many leaders use to enter some other cool trick or a sequence of steps. Still, when it is used abundantly (that means more than 3 consecutive ochos let's say), you have all the right to be annoyed, since it's not the most comfortable step. Anyway, if you are trapped in that kind of a situation, try to work on your pivot and also, any adorno will do.
7. There will be times when your leader will simply stand still in the middle of a song. Enjoy that time and take the opportunity to better adapt your embrace and prepare the next step.
8. The leader will not always make the same steps he leads. He may also lead some steps to you while standing completely still. try to feel his intention and not his steps.
9. Try to always maintain the embrace. Don't give more space than required and don't cover more space than needed.
10. Tango music is usually composed of 8 tempo phrases. A leader should dance to the phrase and stop at the end of a song. However, if he isn't a very good listener, if you feel the song is ending and your leader is still preparing some steps, you can try to slow him down until non-movement by putting more weight into your steps. The feeling for the leader will be that you have suddenly become heavier and that will slow him down.
11. Argentine tango draws its beauty from the liberty of improvising. There is no choreography and therefore, do not expect a certain sequence of steps. Every dance will be different with every leader and with every song.

The second installment in our series of beginner's tips for leaders. Here goes:

1. Keep your shoulders on a horizontal line - don't swing during the dance (that means sideways as well as up/down). Just imagine your follower is trying to read the fine print on your T-shirt. Or - have you seen those Indian ladies carrying tea pots on their heads? That.
2. The order of things is: intention -> follower's step -> leader's step. Even though these all usually happen within half a second, you need to think of them in this order, because your reflex should not be to just walk and make your follower walk, but to make your follower walk, check if he or she did, then walk.
3. When you step forward (and you will be doing a lot of that), make sure your head, your chest and the tip of your foot are on the same vertical front. If your head goes ahead, you lean forward and we already agreed you wouldn't do that; if your foot goes first, that means your follower didn't get the intention yet, has no reason to move and you will step on her toes; if your chest goes first, you'll look like a chicken. The "vertical front" movement is the safest way to ensure that your step will fall under your body, where there's no way you might find the follower's toes.
4. Think at half tempo level. If you feel the tempo beat comes too fast and you have no time to perform your tricks, "overclock" your plan! - think in terms of half tempo, and the tempo will seem like all the time in the world
5. Think at double tempo level. It's harder to do a trick slowly, but it helps a lot. It improves your balance and your leading skills and it forces you to manage the energy better.
6. Do not abuse on the "ochos". They put an unnecessary strain on your follower and they are not a remarkable achievement by themselves. That means, at the end of two successive "ochos" there had better be a stunning trick in your plan, otherwise your follower is entitled to give you a black eye.
7. Do not abuse on the sidesteps either. You know that not very meaningful Tango trick called "standing still"? Well, sidesteps are even less meaningful. So, when in an inspiration crisis, stand still, embrace your follower fondly, make a dreamy face and wait for the next phrase to begin.
8. What you lead to the follower and what you do yourself are two different things which sometimes coincide (for symmetry). You should be able to lead any step (forward/backward/side) to your follower, while performing any of those steps or standing still - all as long as the embrace doesn't break.
9. As far as balance is concerned, you need to mind your own axis and the follower's axis, or rather her or his space. When you invade this space, the follower is in danger of losing balance and thus so are you.
10. Tango music is usually composed of 8 tempo phrases. It is nice not to tap around while a phrase ends and another begins - and it is also nice to stop walking when the music ends. Exactly when the music ends, that is. It is also nice to make a dramatic pose - exactly when the music ends.
11. Don't learn steps. Learn how to lead steps. Whenever you learn a new step or trick, practice it in various sequences, try to start it in different ways and continue it differently. Many times you will learn exercises. Don't just repeat the exercise. As soon as you get the hang of it, vary it. This will also help your followers a lot.

Here are some useful notes for a beginner leader:

1. Step straight forward in full confidence - or you will just end up doing a funny swing, thinking to avoid her feet. Now, stepping on her toes might hurt your dancing relationship, but walking like a duck will definitely kill it. Put your heel down first, and not the way you would if you wanted to kill a bug.
2. When you lead a pivot to your follower, have in mind what comes next and make sure you share that thought. A pivot is much easier if it takes the energy from the previous move
3. Keep a straight pose. Do not seek to help your follower in his or her job by bending inside their space. You will achieve the exact opposite and the couple will look dreadfully.
4. If you do want to help your follower, concentrate on keeping the information flowing in all possible sources: your arms, your upper body, your hips. If your follower can understand what you want, without being a psychic, that makes him or her comfortable
5. Your attention should be shared between your own dance plan, checking if the follower is where you expect him or her to be and checking the environment (i.e. the other pairs, the space, if the wife is looking, etc.). The first factor is up to you. Try to minimize the second and maximize the third.
6. If your follower ends up on the wrong foot (in reference to your dance plan), you have two solutions: - adapt; or -stop. It's OK to pause, adjust your embrace, reset the steps and then start again. Don't pause if you can adapt, but pause, rather than require your follower to adapt.
7. Be firm in your decision, don't hesitate. Make your steps clear and decisive, even if they are wrong. For a follower, being unable to follow what you lead is far better than not knowing what you lead. Partly because the former situation rarely ever happens. Followers are quite resourceful.
8. Never be afraid to ask someone to dance. When you ask, though, be honest about your skills and stick to what can't go wrong - particularly if you have never danced with that person before.

Here are some useful notes for a beginner follower:

1. Do not be afraid to make that back step. If you are given the energy for a big step, do go with it. Whatever you do, try not to kill that energy, since it may give you the force you need in dynamics.
2. When you pivot, make sure you do so on one foot and for starters, with your heels close together. Work on that until you get it right and then you can start playing. :)
3. Keep a straight and pleasant posture, relaxed and comfortable, yet offering some tension in the arms.
4. If you want to help your leader, be sure to make a step only if he gives you the energy for it. Try not to anticipate, but more likely to adapt.
5. If you can, try not to pin point the leader's chest. Instead, try closing the eyes to better feel the couple.
6. A leader doesn't always make the same steps as the ones he leads, so you can't dance just by looking at his feet. And neither should he just by looking at yours.
7. Whatever you do (steps, voleos, giros, ganchos, even mistakes), do so by looking great! :)
8. If you make a mistake, don't stop. A good leader will adapt to it and just go on dancing.
9. Never be afraid to accept a dance invitation. Every tango experience is good experience.

to be continued...

There will never be a step, sequence, or trick in tango that will come close to matching the power of the embrace --Ney Melo.

So, what is the point of the embrace? Well, the first answer would be that we cannot single out one point above all. But here are a few candidates:

1. To connect the partners into a new entity - "The Couple"
2. To channel information from the leader to the follower and the other way around
3. To secure the necessary space under and around the partners, in relation to the other couples dancing around
4. To generate on one side energy and on the other side comfort for the two partners
5. To socialize and make the best of your expensive perfume

In more detail ...

Here are the first 10 hints:
/TODO/ Intro ...

1. It's more about listening than it is about dancing.
2. There are three steps (just three): forwards, backwards and sideways.
3. There are two roles: leader and follower.
4. There are three Tango rhythms: the Tango (classical), the Milonga and the Tango Waltz; the "New Tango" or "Tango Nuevo" can also be seen as a separate branch.
5. Tango is usually danced in a ring, following (and respecting) a counter clockwise direction.
6. The embrace is arguably the most important feature of the dance. It can be open or closed.
7. Most of the time, Tango dancers have all their weight on one foot, whose choice is not (entirely) random.
8. There is (surprisingly) such a thing as a "basic step", or "basico".
9. There are two dancing systems - parallel and crossed.
10. There are many great teachers of Tango touring the world, from which you can learn new tricks.

And now the explanations: