An exercise I use to help make the shooter more conscious of flinch and recoil anticipation/heeling:
Place a SPENT CARTRIDGE on top of the slide after racking it with no magazine and chamber empty. The casing will block the sights, that's OK. Pretend you see the front sight, aim in a safe direction with the rear sight only, and squeeze the trigger. If the casing falls or jerks or tilts, this is lack of follow-thru (pistol is moved). Especially helpful with revolvers and small semiautos.
Just a thought....