Bobitron: Yes, I've done published work for Fantasy Flight Games, Alderac Entertainment (AEG) and White Wolf. I just received my complimentary copy of "Gamma World: Beyond the Horizon" from WW this week which has about half a dozen pen and ink pieces by me in it, always exciting.
Aristotle: Without writing a book on the subject... I've been drawing for as long as I can remember. It's just one of those things where I was always doodling in my notebooks and on random scraps of paper. RPGs were definitely a big inspiration to draw. When my friends and I started playing Palladium's Teenage Mutant Ninja Turtles and Other Strangeness back in junior high, I used to illustrate our characters instead of paying attention in class. Other people getting excited about seeing their imaginations "come to life" on paper is a big part of what makes this type of thing fun for me.
I got into comics around that time too. Jim Lee was a big favorite, as was Chris Bachalo. Outside of comics, I really like Todd Lockwood, Alan Lee, and Brian Froud. All definitely have an influence on my work.
I actually took industrial design in school (Basically: designing furniture, vehicles, and other products to be both aesthetically pleasing and functional.) I find a lot of the same principles apply to designing costumes/characters though. I usually start by doodling/brainstorming elements that I think would suit the character:
This is a page from my notebook. You can see a lot of elements that made it into the final design and a few that didn't (or might make it into one of the other "evolutions" I'll be doing). I like to doodle in pen for a number of reasons: because I find it's cleaner (less smudging), it gives a better idea of what a "finished" version will look like, and it's what I got used to from goofing off in school.
Once I have something like the doodle of the character down in the lower left, I start the final illustration, lightly sketching in the figure and clothing/accessories and then, once I'm happy with how things look, I either ink or go back over with a darker pencil line.
Hope that helps.