Another nifty how-to from Abduzeedo, and the same homeboy who did the gas mask link below this. Pretty advanced, but not a bad area to shoot for if you are looking for realism in a vector world.
Regardless the fact that it's a quite long tutorial, I think the main idea here was not to try to make it identical, but learn the techniques behind the illustration so you can apply to your own projects. I hope you got some good insights and learned more on outline, shading, reflexes and how to add some details to an artwork. Also, don't forget to check out other designs I created for this project.