Lots of games tell you to create a relationship map, but Smallville tells you how to do it.So very true. I played Smallville at Uprising last weekend, and the very next day I ran a game of Don't Rest Your Head. I usually try to scribble my own kind of relationship map when people are crafting characters in DRYH but it's never quite been the most useful diagram. I could glean bits and pieces from it but not quite enough. When I used the Smallville conventions for relationship maps, my DRYH game had a shot in the arm. Things were much clearer for me.
And now I see on Story Games a short thread about the very same thing. The technique is trivial and easy to learn. If you're not already doing something like this, it's worth your time to investigate and learn it. I think your game will be better because of it.