Well, the obvious solution, finding a competent instructor, seems to be out. That leaves a couple other options that I can see.

1. Videotape yourself casting, or have someone tape you. From both sides, from the front, while you are casting at your limit. Send the tape to a pro, like JC here.

2. Come to a fish-in and ask for assistance. This not only gets you assistance but you get to meet and fish with all those nice people.

3. Find a REALLY big riser a couple feet beyond what you can reach, and imagine how big that fish is, and how it would feel to catch it... incentive!