The figure-eight drill is a great way to help you stop slicing the ball. You’re probably taking the club way to the inside in the backswing and going way outside on the downswing. The figure-eight is going to give you this feeling that the club is going on the backswing and then coming down on the inside.
The figure-eight gives a visual picture and then when you go up in your backswing, you turn the corner and make the eight and come down inside. Make sure you put the club down square to your target line.