A golfer's slice is often the most common and most feared of all the faults. A ball curving from left to right for a right handed golfer can cause a lack of distance, a lack of accuracy and years of frustration.
Here is a really nice tip to correct that fault.
A golfer's slice is often caused by a swing path that is classed as out-to-in or called over the top. The over the top move is often caused by a shoulder turn that is not completed to the top of the backswing. This results in the club becoming too far in front of the body and never getting deep enough behind the players chest.
In order to ensure the correct top of the backswing position, try to turn your shoulders as much as you possibly can during your backswing. You should aim to create at least 90° of shoulder turn. This will result in a club that can be more behind your body and your chest at the top of the backswing. In turn, this should result in a downswing that is classed as more inside the line.
Travelling to the ball from the inside line can result in an in-to-out swing path. This, combined with the correct club face position, should result in a ball flight that is longer, straighter and has less slicing spin.
Practice face on into a mirror, and as you start your backswing, focus on turning your front shoulder directly under your chin. If you can create a 90° shoulder rotation, your hands and arms should be further behind you and your slice will be reduced.