If you are slicing too many of your shots, it is more than likely because you are not making a proper shoulder turn.
The key to correcting a slice is to make a full shoulder turn, always ensuring that your left should (if your are a regular right hander) comes up under, or even behind your chin at the top of your backswing.
Now, keeping your head still, start down with your swing so that the right shoulder goes through and comes up under your chin.
Try it. It should help.