One way to tell if you're "flinching" your wrist is to get a dummy round/snap cap, and have a friend load it in the middle of a mag full of live ammo. Since you don't know where it is, you'll feel yourself flinch when you hit the dummy. To correct it (if this is what your doing), just sit at home and dry fire with a quarter on top of the slide. When your trigger pull is smooth enough that the quarter doesn't move, start live firing the same way.