Step 1 Open the face
You should always address the ball with an open clubface in a greenside bunker to avoid digging the club too deep into the sand. Hold the club lightly at the top of the handle and twist the shaft to "dial" the clubface open with your other hand. About 20 degrees open should do the trick for a shot of 10-20 yards.
Step 2 Adjust your base
You want an open stance. Your legs and feet are the base of your swing, so they need to be aimed left of the target. Since you've already opened your clubface, hold it in position and rotate your feet around to the left until the clubface points directly at the flag. Then dig your feet 2 inches into the sand to increase your stability.
Step 3 Vary your pace
Decide the pace of your swing based on the trajectory you need. If the lip is medium to high, swing a little faster than normal to create more momentum through the sand and blast the ball out higher. If you want a lower ball flight and a little run to the shot, swing slower. This allows the clubface to close just a bit as it slides through the sand.
Dial the clubface open about 20 degrees for a 10-20 yard shot.
Mike Adams teaches at Palm Beach Polo Club in Wellington, Fla.