Here is the process for my current project Marvel vs Capcom 2. I get the 'how do you colour or how do you work' question often so here's my way of answering them all at the same time :P
To begin the final Wolverine character art, I cleaned up the thumbnail sketch they chose from a set of four(seen in a previous post . They like the arms posed in one and the legs posed in another so I combined the two. This happens occasionally and luckily the combination worked :)
From there I threw down some quick grey tones to help me visualize the form, gradually 'pulling and pushing' with lights and darks.
Eventually I get to a point where I draw it out with pencil in Sketchbook pro. I don't do this every time - I think I was struggling with Wolverine and couldn't figure it at the time.
Continuing on with the greys I start to chisel out parts giving him a highly exaggerated muscle definition typical of North American comics. I was going for a combination of Capcoms slightly cartoony and anime feel with the over the top anatomy of Marvel comics. This was definitely no easy task! I was told to match the style of my Ryu vs Sagat painting done for Udon's awesome Streetfighter Tribute book. This painting style was very new for me as I usually don't get rid of the line drawing completely. You would be surprised how much more work this creates! You can no longer rely on line to define anything.
I was still bothered by something so I experimented with proportions using the mask tool and resizing the head, legs and torso etc. I realized his head was way too small making his body look really big. Shrinking his legs down and bulking them up also brought him down to his familiar stocky build.
After the grey 'sculpting' was complete, I added a layer set to opacity and proceeded to colour with a brush set to colour mode. 'Other dynamics' and colour dynamics were selected to add subtle variation in otherwise flat colour. This technique was also experimental to me! Here's a tip boys and girls...practice and experiment in your spare time-NOT during a an assignment ;)
Then final touches come with another layer on top set to normal. During this time any loose ends are tidied up and the harsher highlights in the metals are tweaked. The highlights in eyes would normally come here but Wolverine has the typical glow eye look. I will then make a stamp layer (cmd shift E on Macs-not sure for PC's anymore, been awhile since I converted sorry) and adjust with levels and saturation tools.
I hope you enjoyed this quick and dirty tutorial! Stay tuned for more X)