Concentrate on just using your thumb and index fingers. Finger picking is the hardest of the picking techniques, so it may take sometime if your already accustomed to another technique. If your talking about your wrist moving when you change strings when your finger picking. Take it slow like SLY but always make sure your pick is flat when it hit's the string, you don't want that scratchy picking sound that you get from hitting it at an angle. Just relax man and be patient, you keep working at it and you'll get it.