Here is one of my process when it comes to creating some of my illustrations I first start out by drawing everything by hand on a illustration Bristol board typically on 11x17 then I scan it in clean it up in photoshop then begin coloring I first separate everything can flatting all the colors out. After that I start rendering everything by adding shadow values and lighting and other effects. 
Final rendered artwork. 
Spawn and Batman
Published:

Spawn and Batman

Inspired by the classic comics by Todd Mcfarlane and Greg Capullo

Published: