A useful manual for beginning or aspiring map-makers.
First off, if you want to make good maps, you must really take the time to do it. The first ideas you have of nations, federations, wars, etc. for your scenario usually aren't sufficient. For maps, there are major things to remember:
Flag and Vexillological Resources
Tools for Creating Illustrated AH Content
Mapism - For a more humorous, semi-religious take.