Dry snap at a set of phone books, a sand bucket or barrel or a bulletproof vest . Reference : Rule #1 of Cooper .
To stop flinching, you can use the old “ ball and dummy “ drill or the “bump drill “ described on a Bruce Gray video.
The bump drill involves aiming a loaded gun at the target and repeatedly pressing the trigger just short of firing Eventually, the gun will fire accidentally, and you will experience a true “ surprise break “.
You can try shooting at a blank piece of paper. That will teach you to concentrate on sight alignment and not to worry as much about slight wobble in the sight picture.
For lots of instructional video clips : http://www.guntalk.tv/site.php