It used to be that every great player (the likes of Hogan, Nicklaus, Miller) waggled the club at address. Recently, waggling has gone the way of the Dodo. That's too bad, because a good waggle eliminates arm tension and lets your wrists hinge freely. And more wrist action means more power.
A good waggle can also show you the correct path to impact. As you address the ball, flex your left wrist back, creating a cup in your right wrist. Flex it as far as you can, making a 90-degree angle between your left forearm and the shaft, then return the club to its address position. Continue in a nonstop, back-and-forth motion. Now, add a little loop, hinging the clubhead slightly out (as in away from your body) as you waggle back, then back in as you waggle forward.
Try it. It may be the missing link you need for a smooth takeaway and an on-plane swing.