1. To understand your slice angle. The slice angle is the angle the clubface is open to the swing path. The angle the clubface is open to the target and the angle the swing path is from outside-to-inside add together to give you the slice angle. The outside-to-inside swing path and the open clubface combine to make the really big slices. The total angle the clubface is open to the swing path is called the Slice Angle. For example, if you have a straight swing and hit a drive with a 3º open clubface (slice angle of 3º) the ball will wind up about 21 yards off-line to the right. (Fig. 5B) If you hit another drive and your clubface is still at 3º open, but this time your swing is 3º off-line from outside-to-inside, your slice will be double (Fig. 5C). Your slice angle is 6º, meaning, your clubface is, in total, 6º open from the swing path. This will cause a slice of 42 yards. Because of the outside-to-inside swing path, the ball will take off more to the left so it won.t land a full 42 yards to the right. But, even if the shot starts to the left, it may not by playable on a narrow fairway. This is the kind of shot where you aim at the trees on the left and hope the ball doesn.t go into the trees on the right.
2. To identify the type of swing path you currently have. Knowing the type of swing path you currently have is the key to understanding your shots. It is the first step to curing your slice. You need to recognize the type of shot each swing path produces to effectively analyze your swing. Watch the shape of your shots (the way the shots curve). Examine the depth and direction of your divots. This will help you understand your swing path. Identify whether your swing starts from the inside or the outside. An outside-to-inside swing path will cause a slice (or a shot pulled left if the clubface is square or closed). An inside-square-inside swing path is desirable for straight shots and consistency. An inside-to-outside swing path will encourage a hook.
3. To understand the Rule of Seven. For every one degree open your clubface is to the swing path (slice angle) your ball will slice seven yards to the right at 200 yards from the tee. (This can vary slightly depending on clubhead speed and ball type.) For example, if you slice 30 yards off-line (at 200 yards) your slice angle is about 4 degrees. The bigger your slice angle the bigger your slice!

Do's and Don'ts
Examine the scuff marks on the bottom of your driver and other clubs. Those marks are in effect showing you your .slice angle.. The straighter those .slice angle marks,. the straighter the shots you will hit.