I really cant do crap and i was using gimp... I'm really quite horrible at decals and faces...
Although I have made some helmet and space suit decals on photoshop that looked pretty good.
Ill get those up soon enough.
try throwing them up into the modification discussion section. that way you can get some feedback from people prior to releasing it. I mean, granted, most of the comments will be really dumb like "inb4flame" or "this is crap GTFO" so you'll need to weed through them to find some good feedback. don't get discouraged and keep trying!
and if you have photoshop, i'd use that over gimp. although it has alot to do with preference, Photoshop is a much more powerful program. if you want to dive a little deeper into Photoshop a great place to look for tutorials is the tuts plus network
(
Photoshop Tutorials)
learning how to play nice with the pen tool will give you some very pretty results in the end.
Happy designing.