The natural tendency on a greenside sand shot from an upslope is to lean into the slope—and leave the ball short. It may be the most misunderstood shot of all. 

I make sure I lean back with my weight on my right foot. I’m braced on the inside of my right foot, never the outside of the foot. My right shoulder is very low. 

Unlike a normal sand shot, I play the uphill shot with a square clubface (rather than an open face) and let the toe turn over and release through the ball (rather than hold the face open). That way the ball will carry toward the target instead of popping up short.