STEP 1 TO FIX YOUR SLICE: WHERE IS YOUR BODY AIMING?
It is possible your body alignment is too far to the left, especially with the driver. Adjusting your alignment to the right will help get your club path going more down your target line.
STEP 2 TO FIX YOUR SLICE: FIX YOUR GRIP
Your club face might be too open through impact, so adjusting your grip might be all you need to bomb it down the fairway!
Steps to strengthen your grip – leave the clubface square (aiming at your intended start line), then turn both hands slightly to the right (CLOCKWISE)
Your left hand: you should see two or three knuckles and the crease between your thumb and index finger should point towards your right shoulder.
Your right hand: The palm of your right hand should face towards your target (you should be able to see your fingernails) and the crease between your thumb and index finger should point towards your right shoulder.
STEP 3 TO FIX YOUR SLICE: GET MORE DEPTH IN YOUR BACKSWING
What is depth? This simply means that you need to to get a bigger shoulder turn to help get your hands into a better position at the top of your backswing to improve the club path delivery to impact. The big issue I see is the lack of shoulder turn at the top of the swing which causes the golf club and arms to be too steep at the top of the backswing resulting in the dreaded over the top downswing which causes the ball to slice.
STEP 4 TO FIX YOUR SLICE: USE AN OBSTACLE TO GROOVE YOUR SWING
Using an alignment stick inside of a range basket is a simple tool you can use train a better club path. The best part of this training aid is the simplicity; if you hit the alignment stick, you get negative feedback. Do a couple practice swings under the alignment stick before putting a ball into play. This will help promote a better shoulder turn and shallowing the swing plane during the downswing to eliminate the over the top!