The next time you're at the range, try this: Setup and imagine that your derri?re is against a wall. Make a long takeaway so that your hands are at about 8 or 9 o'clock (this drill is only meant for half swings). At this point in your swing, make sure the club shaft is parallel to the imaginary wall.
Try and make a through swing and keep in mind the same goal- to keep the club shaft in front of and parallel to the "wall."
Try this with an "imaginary wall" first and then go ahead and test yourself with a real one (but don't hold me responsible for dings or scratches! :)
Erika Larkin, PGA