here's a quick look how I went about this image. I know, looks like I skipped a lot of information, but these are just key steps...it's up to you guys to fill in the blanks on your own images
On a relative note, I'll be teaching a 10 week class in Los Angeles, starting April 16, on concept art and illustration, covering stuff like this and so much more. So if you wanna learn all deez tricks, come on out!
Here's the school: [link]