All in the setup: If you match your hips and shoulders to the angle of the slope (inset top), you'll set up solid contact. If you press into the hill (inset above), you'll swing steep and tend to hit it fat.
1. Align your body with the hill.
Try to get your hips and shoulders parallel to the angle of the slope (inset, top). This might be tough to do on severe slopes, but the closer you get to parallel, the easier it'll be to make solid contact. Many golfers lean into the hill (inset, bottom), leading to a steep, choppy swing.
2. Play the ball in the middle.
Because you've adjusted your body to the hill, there's no reason to position the ball differently than you do for a standard pitch. In effect, you've created a level lie -- except the upslope adds loft to the clubface. To allow for the extra loft, take a less-lofted club or play for a higher shot.
3. Swing with the slope.
The right setup will help you swing up the hill, but it's a good idea to remind yourself. Swing the club down the slope going back and up the slope through impact. Remember, you don't have to help this shot get airborne.
Sorenstam runs the Annika Academy at Ginn Reunion Resort near Orlando. Click here for a video of Annika demonstrating her swing tips.