Good Skinning Tut

I want to learn how to use photoshop to make skins for my models; ORIGINAL skins, not generals skins, my own. Does anybody have a link that tells how to make a good camo skin or at least teach me some of the ins and outs of making a skin using Photoshop 7? Preferably for tanks and aircraft? And i dotn mean killas tuts, no offence killa, but i want all the stuff i make to be mine and original.