What Are the Causes of a Golf Slice?

Your set-up will have a direct effect on your swing path. When you look down, your feet, knees, hips and shoulders should be on the same vertical plane. If any one is open to your target line that will cause an outside-in swing path. During the downswing your hands will drop in towards your body. This opens the clubface and puts left to right spin on the ball (right-handed).

Decelerating through impact is a big problem for amateurs. Slowing down to guide the clubface into impact opens the clubface. Your hands are already leading the clubhead; when you decelerate, you don't rotate your wrists through impact. Always accelerate through impact on all of your shots. Think about your swing speed being the fastest just AFTER impact. That technique will ensure that you accelerate.

As you make your backswing, your weight shifts more toward your back leg. On the transition to your downswing, your weight shifts back toward center and eventually to your forward foot on your follow-through. If you don't make that weight shift from your back foot to your forward foot, your "center" will be too far behind the ball. This results in reaching for the ball and making contact with an open clubface. A weak slice will be the result every time.