I know quite the bit about skinning, this is my latest work for a HL mod:
http://hostagesituation.mypunbb.com/viewtopic.php?id=31
I also had quite a lot of trouble creating textures, down in the end i was abusing cloud and noise filter in PS. Now you might say, how the hell did he learned it? By tutorials, yes there out there and there plenty of them.
But, up to a while ago it was a certain thing about skinning that you need to understand, i still cant put my finger on it but i definately changed something in my mind that helped me understanding the texture.
Enough blattering from me, check this link out:
http://www.sourceblog.org/
Nowadays you need to sign up to see the tutorial database but its worth it. The forums arent to crowded but those people really know what there talking about.
Good luck, and if you need a hand feel free to contact me, helping doesnt hurt anyone.
Dodge and Burn are tools with wich you can (respectively) lighten or darken a area. Thus used to create a base skin, then small details painted in by changing the lighting.