Thanks Fish for your response; however, I'm looking for a means by which I can clearly illustrate the difference between something I "would do" in the past and something I "used to do."
Today I had my students write down one sentence using "used to." Then I had a five or six of them write those sentences on the board and carried their ideas further by using "would." For example: I used to have long hair. I would wash it every night and then my mother would brush it for me. Sometimes I would wear it in a pony tail and other times I would just let it hang naturally. Another one was: I used to argue with my father. We would often argue about the clothes I wanted to wear to school. And we would argue about the things I chose to spend my money on.

Well, you get the idea. The above went over pretty well, but I still have the feeling that it's a cloudy concept. They get the idea that both can be used for repeated actions in the past. But when to choose one over the other has only sunk in a little bit.

Any ideas on how to get this across? It's kind of interesting huh? I mean it's a pretty obscure language point that, though introduced in a few texts for EFL/ESL students, has not been presented in a way that creates an adequate understanding.

Your input is most appreciated.