Quick Tip from Mark Rolfing:
To properly execute a greenside bunker shot you want to splash the ball out of the sand. For most PGA Tour players this is a very easy shot and it can be for you too
First you need to understand the design of a sand wedge... It has a lot of loft and a bounce sole. This sole is the part of the club that you want to do the work. You do not want the leading edge, to enter the sand first
When you address the ball in a greenside bunker set up in an open position left of the target. Open the clubface significantly and use a swing path that goes from outside to in . . . down your body line. The open clubface will propel the ball toward the target.
Most average players have trouble with distance control on their bunker shots. It is important to know that it's not the length of your backswing that determines how far the ball travels. It is the length of your follow through.
For a short shot, I simply cut off my follow through at about knee high. For a longer shot, I hit the sand in the same place, behind the ball, but simply have a longer follow through.
Utilize these tips and you can be a better bunker player.