Tour players make even the trickiest sand shots look easy, but you can run into trouble if you don't know what adjustments to make when you're presented with something other than a level lie. When you have an uphill or downhill lie, you need to tweak your setup and swing to make sure you're successful getting out.
The overall concept is to keep your body perpendicular to the slope of the ground throughout the shot. For an uphill lie, tilt your spine away from the target, and be sure you don't drop your left shoulder and lean into the slope as a way of maintaining balance. The opposite is true for a downhill lie: Don't let your right shoulder drop to brace your body against the hill. Just focus on setting your spine at a right angle to the slope.
The uphill shot is the easier one, because the slope helps you get the ball up in the air. Use your most-lofted wedge, set your weight forward, angle your toes toward the target, and swing into the sand just behind the ball. The ball will come out higher and softer on this shot, so make a slightly bigger swing.
On the downhill shot, resist the urge to try to flip the ball up and out with your hands. Take a slightly wider stance, swing the club along the slope, and let the loft of your wedge do the work. This shot's going to run out more, so that might mean playing away from the flag to a fatter part of the green.
__1. UPHILL: Tilt your spine back so it's perpendicular to the slope.