When playing a bunker shot play the ball off your front heel and make sure that you hit only several inches behind the ball so that the bottom of your swing arc is directly under the ball
Hitting the ball with the sweet spot of the putter allows the putter face to stay square and not twist
With a traffic cone behind you practice your downswing trying to keep the club inside the cone to simulate the correct approach at impact, this will help eliminate casting, over the top and other downswing faults that create curved shots and an improper impact position