I think after years of education, I finally figured out how to make a good thesis: Write the paper, and then see what you argued. As opposed to coming up with either a really lame thesis, or saying something and then going off on a (hopefully better) tangent and never coming back. Which is what I was previously doing.

And to think, I only came up with this because my paper was going to be twice as long as the assignment said and I needed a new strategy for shortening it. So I decided to write and see what my main theme was, and then go with that. Hoorah! Now off to finish said paper.