Just wanted to add:
Now, I've been only in this game for about six years now, but maybe this could help if you haven't already solved the problem. If you have access to a fiberglass rod, I suggest practicing with it. If you started out casting grahpite, the slow action will prove challenging at first, but it will do several things more effectively. You will be forced to accelerate more slowly and in a longer arc, giving more time to analize your cast, load your rod and improve your timing. Secondly, a Fiberglass rod (or otherwise slow graphite) will force you to use your arm and wrist to dampen it after the abrupt stop the "flings" the line forward; in other words the moment the rod releases its load, the line, you use your arm to absorb the shock waves that continue to travel down the rod. My guess is that your stop is too abrupt. While it's important to accelerate smoothly, it's like-wise important to dampen the rod and stop smoothly after the initial halt. This doesn't mean cast with a loose wrist (although styles vary so greatly, this is pertinent to an overhead, basic cast.), but more once the rod has exerted all of its good, line flinging energy, stop the wiggles in the rod that will cause such oddities in your cast, such as "waves".