Curing the golf slice requires you to fully understand the whole swing and how exactly a slice occurs. Here is the mechanical explanation behind a golf slice. Slice is a term describing a specific left-to-right type of trajectory of the golf ball for right-handers, the opposite is true for lefties. Either way, a slice ends up right (or left) of the target line. Every golfer tries to hit the ball squarely and straight, but if the club face is slight open at the point of action in one direction, it will cause the ball to spin which will ultimately make the ball go left or right. Right-handers spin the ball clockwise when they slice, the friction which results from this spin makes the ball go to the right.
The most common reason for a slice is the grip is too weak and too tight with the handle in the palm's tree. To avoid the slice, you must hit the ball with the clubface being straight, not twisted to the left or right. If you want to get an idea where exactly you are hitting the ball with your golf club, glue a tee to a magnet and place it in the center of your clubface, then make slow-motion swings to learn where your face points during all points of your swing.
There are some must-have elements to add to your motion for curing the golf slice. Rule number one is to have your clubface pointing in the same direction as your right hand. At the moment of impact, your right hand should face the ball. Make sure your motion is controllable, it's about gently swinging the club, not haking it. If you look at how Pro golfers do it, you will see that they don't put much pressure into their swing, they do it almost effortlessly. Even a slight overswing will result in a slice, so you have to be very precise. Practice makes perfect.