Mark Durland: Your Path to Better Shots (May 2014)
If you hit a lot of slices and pulls, your swing probably cuts across the ball from out to in. A drill for this is to set up to the ball and make a practice swing as if you were playing to a target straight out from your chest--90 degrees from your actual target. This "sideways" swing will give you the sensation that your shoulders stay closed to the target into impact. After three or four swings, hit a normal shot and try to re-create that feel.