Amateurs have a hard time getting out of the sand. But pros don't. Pros know how to hit it correctly. If you understand how to hit your bunker shots, bunker shots might just become your favorite.
How to Set Up for the Shot
1. Rotate the face open first before taking your grip
2. Grip your sand wedge. The face should be facing right
3. Align your shoulders and feet left of the flag until the face of the sand wedge points at the flat of your target
4. Position your ball left of center
5. Dig your feet a little into the sand so that you won't slip
6. Flex your knees little more than usual pitch shots lower your center of gravity
The more you open your face, the higher the ball will go up in the air. So you need to experiment how much you rotate your face open. Dave Pelz said to rotate your face 45 degrees to the right. Most golfers grip the club first and then open the face. If you do this, the face will close at impact causing you to dig too mcuh or hit it left. So make sure you open the face first and then grip it.
The Swing from a Bunker
Backswing: Set your wrist early on the backswing. Make sure to take the club back along your feet or shoulder line.
Impact: You don't want to hit the ball. Aim at the spot 2 inches behind the ball and try to slide your sand wedge under the ball.
From a bunker, try to feel like you are hitting sand instead of a golf ball to the target. So practice hitting sand without a ball. Try to splash the sand out of the bunker. Also, you are aligning left of the flag. So try to cut across the ball. Swing along your feet line.
Follow through: You need to swing left of the flag because you are aligning left. Make sure you don't turn your face over for a bunker shot.
How much Sand to Take
Basically for bunker shots, you should try to slide your clubhead under the ball. You never want to dig your clubhead deep into the sand. I said to aim the spot 2 inches behind the ball. But if you want the ball to roll after it hits the green, you might want to take more sand. In this case, aim for a spot that is about 3 inches behind the ball.
If you take more sand, the ball won't spin as much. So it rolls more. On the other hand, if you want the ball to stop quickly, aim 1 inch behind the ball and take less sand. The shot will fly higher with more spin.
Accelerate through Impact
The sand provides resistance as a clubhead slides through the sand. That's why you need to take bigger swing from the sand. The common mistake among average players is to decelerate through impact. So make sure you accelerate through impact.
2 Ways to Control Distance
There are 2 ways to control distance from sand.
1. Take bigger swing
This should be easy. Take bigger backswing. Just make sure to accelerate through impact. Some golfers take a big backswing and accelerate through impact to adjust distance. This won't work well.
2. Change your set-up
Lots of green to work with
When you have lots of green to work with, you might want the ball to roll more after if hits the green. Rolling the ball is much easier than flying it all the way to the flat with more spin. If you plan on rolling the ball more, you don't want to open the face as much as you do for normal bunker shots. If you open your face less than normal, you don't have to open your shoulders and feet so much as well. This will make you to hit it lower than normla with less spin.
Less green to work with
If you don't have much green to work with, you want to hit it high with more spin so that it stops quickly once it hits the green. For this shot, open your face more before gripping the club and then grip it. You need to open your body as well. This will add loft at impact casing the ball to fly higher with more spin.
Reference: http://www.golfsamurai.net/short-game/how-to-hit-the-bunker-shot.htm