I'm assuming you mean for jumping? Simplest most effective one I know is to set up what would be a bounce if you raised the caveletti. Having the pole on the ground about a stride away from the takeoff point REALLY helped my guy, he used to get nervous and jump wayyyy to far off and have to work much harder than he had to get over the jump. His distances are quite nice now :]
My horse used to rush jumps occasionally. Trot over the cavaletti, halt as soon as possible. Stand a moment, then turn on the hind, pick up a trot and go over the cavelletti. Stop as soon as possible and repeat. Do this until the horse is listening to you for cues. Anytime my girl rushes the fences, I pull out this exercise. It works as well for jumps as cavelleti.
I would try setting up the cavaletti 3 strides apart. Make sure your horse does it in 3! I would also recommend putting something different on it (like a towel, etc) to make him look at it and be more catious. Make him think you know all the tricks in the book, by this I mean make him go straight after the jumps, right up to the fence. Obviously stop at the fence. This will help him listen to you. I also agree with the bounce, or a line of bounces, because it will force him to rock back on his haunches and slow down.