Since many of us have a tendency to "come up" on some of our shots, usually the most important ones, how about compiling a list of techniques for helping a player stay down as they pull the trigger on a shot? I'll start off with a few I have run across.
1) Nick Varner said it helps you to stay down if you always try to watch the cue ball hit the object ball. A more extreme version is to try to stay down and still until you see the object ball go into the pocket. Just remind yourself, as part of your pre-shot routine, to watch the cue ball hit the object ball.
2) Incorporate into your pre-shot routine the thought, as you drop down on the shot, the sage advice of Jay Helfert, "Be still."
3) My friend Billy Carrelli offered two solutions. He said when he worked on this problem within himself, he would imagine that he was playing in a room with a very low ceiling, just a couple of inches above his head when he was down on a shot.
3a) Billy other suggestion was to have a friend with a ping pong paddle stand near you as you shoot and whack you on the head real hard if you raised up on the shot. He predicted it would take only a couple of whacks to cure the problem.
4) Put a 40 pound weight on the floor between your legs. Tie one end of a piece of twine to the weight and loop the other end around your scrotal sac. Just be sure there is no slack in the twine as you are down on the shot.
5) A poster here on AZ (Colin Colenso?) suggested that a player who raises up on his shot did really drop down on the shot with the INTENTION of staying down through the shot. I have noticed that when I am nervous about a shot, I can just feel, as I drop down to the table, that my body is preparing to "bail out" and come up rather than stay down. So it might help for you to think, as you move down to the table for the shot, "I am settling in and staying down on this one."
6) Add your suggestions here.