Download this poster to have some of the tips from GIS Cartography: A Guide to Effective Map Design at-hand for easy reference.
It dresses up an office wall nicely. Just click on the thumbnail image on the right to access the full-size version. It's 18" by 24" — Arch C — so you'll need to use your large-format printer.
Poster Design: Susan Murray
Map Design: Gretchen Peterson