The most common reason people slice is because they have a grip which promotes a slice. What I mean by that is that their hands are turned too far to the left on the grip so when they come back to impact their hands naturally open, thereby creating the slice. To get the correct grip what you want to do is turn your hand around so that your left thumb is more to the back of the shaft, your left hand is more on top of the grip and the right hand comes in facing the direction you want to go. A good way to check and make sure you have the correct grip is to use the two-tee drill. Just take a tee and stick it into the gap between the thumb and first finger of the left hand. Do the same with the right hand, and you will be able to tell automatically if you have the correct grip if both of the tees are on line over the top of the grip. This is the best way I know to fix a slice.