I have this bookmarked somewhere on my computer from the first time I stumbled across it. I really, really like these rules.
#19 is my favorite.
It should always be much easier to get into trouble than it should be to get out. I don't like luck getting characters out of trouble, or things just happening to line up. It's not that it doesn't (sometimes) happen that way sometimes in real life, but that it doesn't make for a good story.