Teaching a horse consistency in trot and canter?

I train horses on and off the track. some exercises that i love to use i call rating exercises. You see when you train a horse to run you want them to be harder in the mouth so they don't over react to commands the exercise rider or jockey might give them. So when you soften your hands he thinks "Oh she's letting me go!" and he gets excited. the first thing i always do is change the horses bit. That takes him out of his familiar endowment and sets him in a knew training atmosphere.(I recommend a slow twist snaffle) You can start with taking him at the walk and stopping him, then i always have a horse back at least two steps. do this at the walk and trot until you get an almost immediate response then progress to the canter. it is critical that you get him really thinking and reacting to your hands. eventually when you canter him and he starts to speed up all you really should have to do is raise your hands slightly and he will respond to the pressure and listen to the pace that you ask him for. i would do some leg yield exercises as well. this will make him supple and more responsive.