For the last while I've been playing with maps that generally speaking are either going to be displayed on a computer screen or printed on a full color laser printer.

Needless to say, they don't look so hot if you have to print them on a black and white printer that's capable of greyscale. What sort of qualities does a map need to have if it's going to be printed like this?

I guess my question is really, if I'm drawing a map with the intention of including it in a product that someone else might want to print, what should it look like?