Curing a slice is all about controlling the angle of the club face. Amateurs who are plagued by this mishit struggle to deliver a square swing path and a square club face at impact — the shaft of the club is too vertical at the point of contact.
Here’s a simple drill that will help you correct that slice once and for all. Make a short backswing, then create a little flexion with your lead wrist. That’s the angle at which you’ll want to keep your hands through impact. Finish the swing and watch the quality of your contact improve.