A good filing cabinet organisation system is great, but if you don't need a full cabinet (or don't have space for one), weblog Unplggd offers a simple DIY solution.
You could always grab a smaller file box to store your paper, but you either have to stick them on top of your desk—taking up a lot of space—or somewhere out of the way, which doesn't make them quickly accessible. Clever IKEA hacker Thomas, however, came up with a better solution. He took a $15 pack of two IKEA shelf brackets turned them on their side, and mounted them to the side of his desk. That way, all his physical documents are close by, and don't take up the space that a filing cabinet or desktop file box might waste. (He's also using a handy binder clip trick to keep the folders from sliding around.) Hit the link to see more.