Make sure your shoulders don't turn more than 90 degrees past their starting position -- check them at the finish.
A slice comes from only one condition: The clubface is open at impact, which puts cut spin on the ball. One of the most common causes of this open clubface is improper rotation of the upper body. On the downswing, the shoulders turn earlier and faster than the arms and club swing. As a result, the clubhead trails and comes down to the ball heel-first -- creating a wide-open face and shots that curve right.
To solve this issue, work on two swing thoughts. First, feel that you're keeping your back to the target at the top for an extra beat as you start your arms and hands down toward the ball. Second, make sure your shoulders don't turn more than 90 degrees past their starting position -- check them at the finish.
This is a great indication that your hands, arms and body are timed together and working in the correct sequence through the ball. As a bonus, you're sure to make better contact and get more distance with less effort.
Hank Haney, a Golf Digest Teaching Professional, runs the Hank Haney International Junior Golf Academy in Hilton Head.