When teaching a new manoeuvre, get the feet to move in the direction you want them to go and then put the finishing touches on it later. This applies especially to the gait quality.
Horses learn patterns very well. If you can establish the pattern in the horse's mind then you can adjust the speed and length of stride later.
Let's use the example of teaching leg yielding. I tend to do this in a few different patterns but a good one is to use the long side of the arena, do a half 10m circle at the end and then leg yield back to the track. Repeat the process at the other end of the long side, leg yielding back to the track again.
The horse soon learns the pattern in walk. I then move to trot but allow the horse to jog for a while to keep the emotional level down. Once the horse has established the same pattern in jog I ask him to improve the stride.
Using this 'pattern establishment' method keeps the emotional level of the horse stable and allows him the time and mental clarity to learn the manoeuvre.
1) Get the feet to move
2) Take the feet in the direction you want them to go
3) Make it pretty - speed, quality of gait, length of stride