I have found during my teaching career that chronic slicers of the ball have two faults in common: a weak grip and a tendency to fan the club open early in the backswing. If you have always fought a slice do these two things to cure it.
First, adjust your grip so you can see 2-3 knuckles on your left hand, and the V's formed between the thumbs and forefingers of both hands are pointed at your right shoulder. Your left hand will feel more on top of the grip and your right hand will feel more under the grip.
Second, keep the club facing the ball as you begin your backswing. The feeling will be of the club facing downward rather than skyward until it reaches waist high.
These two adjustments will deliver a square clubface at impact so the ball will no longer curve to the right.