Many players who slice their tee shots will instinctively set up well open to the target to either neutralize or play for their left-to-right ball flight. But aiming left only accentuates the problem by encouraging an out-to-in swing path through impact, which makes a slice even bigger.
This open position generally starts with the eyes aiming too far to the left at address (above right). Learning to set your eye line directly at or to the right of the target automatically squares up your body (above left). Square body alignment promotes an in-to-out downswing, which is crucial to turning a weak banana ball into a strong draw down the fairway.
David Leadbetter is a Golf Digest Teaching Professional based at ChampionsGate near Orlando. He operates 26 golf academies worldwide.