Okay, so here's my more in-depth answer.
First, some useful links on the subject:viewtopic.php?f=8&t=4121
This is Romy explaining bodylanguage, how it varies with people, and some ideas to work on improving communication via body language.viewtopic.php?f=27&t=605
On how to teach a horse to jambette (a lot of it isn't based on mimicry, but enough is that it may be valuable to look at this)viewtopic.php?f=27&t=2701
On ramener: it's heavily based on body language and mimicry, especially after the horse has already learned itviewtopic.php?f=27&t=4262
The school halt: kind of advanced (for both person and horse), but it is, once again, very heavily based on mimicry.viewtopic.php?f=14&t=4409&p=85643&hilit=mimicry#p85643
Here's a short discussion about mimicry
If you want to find more on the subject, go to the home page of this forum. It has an area where you can search for key words. A fast look at it shows 13 pages of results. It you can't tell, we talk about mimicry a lot. When To Use It
Mimicry is good for a lot of uses. During training, when you're teaching the horse to do things, it is incredibly useful. That's why you'll find it in so many of the exercises. You can also use your body language to calm a horse down or get them excited. Horses are such social animals that they take a lot of cues from others. In fact, your horse is probably already watching and mimicking you to a small extent without you noticing. They note where your attention is, how you respond to certain objects and situations, and how you do something you try to teach them.How To Use It
This is a bit more difficult to say. The first step would be noting everything about your body position. Know exactly how your body is oriented in space. A possible exercise to learn how to do it is this: stand in front of a mirror and shift your weight slowly. The soonest you can see a motion, note it. Try making your movements as small as possible, and try to see the smallest movements. That is what the horse looks for-movement. Here's a brief interlude from talking about mimicry (I promise it's relevant):On Differences of Perception
People's eyes are designed to see colors. We see 6 main colors, but thousands of variants caused by combinations of those colors, different shades, lighting conditions, etc. People notice color, then shape before almost anything. Our eyes are very precise; we don't look at an entire scene, but a very specific part of the scene. For instance, when you walk into a room, you don't notice the whole room at first. You look at people, furniture, the walls. What you don't do is see it all together, because that would be too much to process. This specificity allows us to read, because our eyes look for the small details rather than the larger picture. Horses, however, don't see like we do. Remember that they have about 350 degrees of sight, while we only have 180. Horses can only see blues, greens, and yellows (so I've heard- not entirely sure if that's true). They don't look for color or shape. Horses look for movement. Through evolution, they have been trained to watch the bushes for rustling that could be a predator. They have learned to watch other horses to see it the other horse notices something they don't. Horses perceive the world differently because while people look for specific things like colors and shapes, horses look for movement. And they are very good at finding it. They see a lot of things we don't, not because we can't, but because we don't look for it like horses do. One cool thing you can do to see the world as horses see it is to try to look for that movement yourself. You'd be surprised at how much movement you can see, when you normally ignore it. Just watch for the movement instead of the specific colors and things that people typically look for. It's quite interesting to notice things you see every day, but never really note.Back to Mimicry...
So anyway, the purpose for that is to explain why horses mimic us the way they do. You can hold a pose and hope for the horse to do the same, but that doesn't work. Horses need to see the movement in order to pay attention to it. For instance, if you want your horse to shift it's weight back, don't just stand there with your own weight back. Your horse needs to see you moving to understand what you want. Horses communicate with each other by movement. If you ever go out to a field of horses, watch how they communicate. Some movements are tiny, barely noticeable, and others are obvious, moving the whole body. The best way to learn how to interact with horses is to both see how horses interact with each other, and by practicing interacting with them yourself. Try doing a simple movement, and see if your horse responds. You might not see a response, but that doesn't mean that the horse didn't. They could have either done something different from what you expected or done something too small for you to notice. However, some horses that aren't used to interacting with people at liberty might not realize you want them to react. That's okay if that's the case. Just keep watching your own body language and how the horse responds, and you'll start to see it soon.