Mostly, we go about our days thinking and noticing very little about our movement - we do what feels natural until something bothers us. Then, we squirm around a bit until the uncomfortable feeling passes.
Sometimes though, we want or need to change our movement. The thing is that movement is largely an unconscious process full of habits, old perceptions, and challenges of balance and tensions. So in reality, it doesn't just change with a snap of our fingers.
There are many ways to change movement and get some kind of result. Sometimes good, sometimes not so good. But to create a completely new expression of movement is a real art.
Here's what happens:
First, before we move, we unconsciously predict and sense: Ourselves, our movement to come, and the environment we move in.
Then, we move, and perceive our senses to see if they match what we thought would happen.
If what we sense doesn't match our guess, then a new movement may have happened and we learn.
A completely new movement is different that what we thought would happen. Otherwise it's something we already know, and it's not really a new action.
Thus, to create a truly new movement or action and learn something new, we have to be wrong about both what we think will happen, and what the movement will feel like.
The game is catch yourself as you guess wrong, then to stay out of the way of trying to fix it to make it 'right'...to let a new movement (or pattern of movement) show up on it's own.