Nice response jase. People like you are the reason the world is heading straight towards hell.
Im in your position mate, I know some, plus I know how to handle photoshop so Im okay to atleast start. Problem atm is that Noone seems to know how to get ahold of the origins skin files extracted (the come compressed with the game) except for the fmf extractor ebta program which currently Ter cant send to anyone, he has sent to a few already but other than those I think peoples hands are tied.
But in general regards to your question. Some programming skills is required if you are interested in fully customizing it, otherwise some photoshopping/similar program is needed to change appearance and colors. There is a guide somewhere on Susie made by someone called Seafire/seafoam that may help you a bit.
www.sortitoutsi.net check the forums.
How do you make skins? 
Linear Mode
