Ryan Connolly over at FilmRiot recently recommended this tutorial and it is pretty amazing. In 30 minutes it teaches you pretty much everything you need to know about composing your scenes. It is aimed at 3d/Computer Graphics artists, but, since filmmakers in a sense ARE 3d graphic artists I found everything Andrew Price says in this tutorial spot on.
Andrew breaks down the tutorial into 3 principles – Focal Element (what you are looking at), Structure (where you put it) and Balance (how it fits in with the rest of the scene). Master this – or at least be aware of it – and your images (still, animated, live action video) will be that much more appealing. If I wasn’t so lazy I’d do a matching video with film examples, but, I am lazy.