You've probably heard that to chip the ball effectively, you have to keep your weight on your front foot throughout the swing. However, even with most of your weight forward, it's still possible to swing up on the ball. That's what can happen if you don't get your upper body--including your head--in line with the ball's position or leaning slightly toward the target. The width of your stance has a lot to do with proper body positioning, and that's a major factor in hitting solid chip shots.
If you set up with a wide stance, it's easy to hang back with your upper body and have your spine tilting away from the target (above, left). More often than not, you'll hit your chip shots fat or thin from this position. Instead, set up with a narrow stance and feel that your whole body is leaning slightly toward the target (middle).
When you swing, maintain this body-forward position (right), as it will encourage you to keep your hands ahead of the clubhead past impact. You're allowing the club to work down and through the shot--ideal for crisp contact.
David Leadbetter is a Golf Digest Teaching Professional based at ChampionsGate near Orlando. He operates 26 golf academies worldwide.