Well, one thing that's messing me up right now is that this canal often doesn't give you any room at all to backcast. So I'm having to try the Steeple cast, and the cast where Lefty throws it into a hole in the bushes (Galloway cast?). Obviously I get hung up on the trees every now and again. Fortunately, since I'm fishing for carp and bass, my tippet is 20 lb. test so I usually get the fly back.
Every now and again there is a short stretch where I can do a normal backcast and a normal forward cast. I've also got a video by Doug Swisher and while I don't like the way that his casting looks compared to Lefty, there are some useful tips for practice. For example, he tries to throw loops through a tire. I really should try to do something like that to help me with my backcasts into the bushes. If I ever get that down, then I'm going to start working on curve casts. The straight line cast is pretty much all I know now.
Thanks for the tip on trying to hit the tip of the rod with the line. I'm going to try that tomorrow.