what i have done is the ball and dummie drill by myself. if you don't know what the ball and dummie drill is, google it. this is usually done with 2 people at 3 yds, but can be done by yourself.
i take 10 mags and 5 live rounds and 5 dummy rounds. i load only one round in each mag, that gives you 5 dummy mags and 5 live mags. put the 10 mags in my range bag. i look up at the sky, grab a mag, rack the slide and load the round. i have no idea if it's a dummie or a live round...that's the whole point. take aim at a bulls eye of some sort and press the trigger. if you have a flinch and a dummy round, you'll see yourself drop the front of the pistol. if you have a live round, you'll drop the shot.
maybe incorporate that into your train regime next time you go to the range. when you see yourself dropping shots, do some ball and dummy rounds.
to ad to the drill, i do this like we would with a dot drill with rifles. i take 10 dummy rounds and 20, 30 live rounds and dumped them all in a bag. i look up at the sky, grab a few rounds from the mixed bag, and load those into a mag. you can 2, 3, 5, 8 rounds...whatever you wanna do. then take those few mags, toss them in your range bag, look up at the sky, reach in and grab a mag. now you have no idea how many rounds you have, and how many live rounds or dummy rounds in each mag. the purpose of the drill is the same principal. aim at each dot, press the trigger and you go boom or you go click; and you drop the front sight/shot or you don't. this is what helped me get over my trigger snatch.