I'll let Jay provide the details of the drill (I hate typing), but LAV has the best solution to this that I've seen. He calls it the Dummy and Ball Drill. The reason you can pull the trigger perfectly in dry fire but not live is because you have two boxes in your head. One tells you how to pull the trigger on an empty gun, and the other tells you how to do it on a loaded gun. You need those two boxes to come together, so that your finger (and your mind) only know one way to pull the trigger.
The other mostly overlooked aspect of this is that trigger control may not be your issue. Anticipation of recoil is far more destructive to most people's accuracy than trigger control, and it usually gets misdiagnosed by school trained instructors.