Most has been covered for training the horse.
Think about your cues though when you're training, and how you want it to be when you're showing.
Mine, vocally know to set up and recognize "front" and "hind" when I say it during the beginning stages. I slowly wean them off the voice command, and they start setting up from me just looking at whichever hoof. It's crisper.
Lots of practice, and what everyone else has said. I prefer not to practice without a chain, so I suggest always practicing with it. I want it to be how it be will in the show ring. No surprises.