Simplify a long bunker shot by changing your club, not your technique. Instead of squaring up your sand wedge to gain added distance, reach for your pitching wedge and play it like a shorter blast.
Open the face of your pitching wedge at address so it points slightly right of the target. This will expose the club's bounce, or trailing edge, which prevents it from digging into the sand -- and your shot from coming up short of the green. Now use your normal greenside bunker swing, making sure to accelerate the club into a full finish.
The ball should splash out and travel the necessary yardage to the flag.