Dry firing, ball and dummy, volume. Volume is key to speed in my experience. I can shoot accurately all day long, I can do it after not shooting for two months, but if I want to shoot and move fast as IPSC requires I need to have a high volume of practice. For action shooting in the early stages, once you have accuracy down, I find practicing reloading and moving and timing your reloads to be more important then the actual speed with which you shoot. Most of my time in a course is spent moving and transitioning, my shooting is actually a small portion of my total time.
One difficult thing that I am struggling with is shooting on the move, I want to get to the point where I can shoot roughly the same standing still or moving within 50ft. I practice waddling a couple times a week in my apartment.
Ball and dummy, mix snap caps into the magazine with live ammo. Try and find a way so that you don't know which is a snap cap and which is live. Go shoot, if you see yourself flinching when the snap cap comes up you know you have a problem. I think the ball and dummy is useful but only to a point, you should be able to call your shots with out the dummy, if you can't then you may not be paying attention to your trigger control. Experts may be able to point out somethign I am missing.
I always get a kick out of action shooting considering 50 ft. a long shot, 50 ft is short range (gallery style excluded), 25 yards is where long begins, 50 yards is long for a target the size of the IPSC Charlie zone. Any action shooters out there who consider 50 ft. short?