you may be anticipating the recoil, which makes you jerk the trigger.
what i suggest to practice, put a dime balanced on the end of the barrel and dryfire. the dime should not fall off. use snap caps to save the firing pin. practice until the dime does not, or barely moves. it will also help...
shoot the fool as he busts through the door because my pistol is ALWAYS in arms reach of me, then call 911 and tell em to send the meat wagon.
as far as clearing, that's really if you come home and find your house has been broken into. and legally on that, I would say stay outside and call...