This is my entry for this week's #SketchMatch challenge. They post one every week on: http://twitter.com/sketchmatch and upload it to FB and tumblr. They also have some random 10 minute matches that totally rock!! Be sure to check 'em out.

Below is all the walkthru process it took to finish this in about 3 hours.
First, the sketched pose and then a more detailed sketch followed by a color block in and flats.

 

Then a shadow scheme and after that I get more into it with the mask, lights and shadows in general.

After that I import the t-shirt logo and apply the "displace" filter to it in oder to make it placed in a more natural way on the t-shirt.

Then I merge my whole charcter in a single layer and duplicate it above just to apply the "Lighting fx" filter to it.
After applying it, I give it the "Overlay" blending mode and reduce its opacity to 25%.

This is the result of what I explained above.

Now I take my photo reference for the BG and paint over it according to the light effect I want to approach.

We are almost done now.
Now I add some nice blue reflective light and then a shadow and we are done.
Scroll up to see the final result again! :D
Hope you dig it! Cheers!