For bunker shots longer than 10 yards...

Release the club like you do when you're hitting approach shots from the fairway. You don't need a full finish. What's important is that you release the clubhead so that your left palm faces the sky. You know you're doing it right when the clubhead finishes high above your hands. This type of release adds extra oomph to your sand swing, helping you to fly the ball all the way to the hole.