Here's the process behind my latest piece, which is a digital painting inspired by the SCP Foundation Wiki as well as the Survival Horror game based on the site.
This shows pretty much how the piece was created, from beginning to end.
Some thumbnails I drew at work
First loose sketch
Refined lines, details finalized
After messing around in painter for a while I couldn't create a background for the scene that I was satisfied with, so I booted up Sketchup and recreated a section of hallway from the game.
With the background in place and the sketches imported, you can see the beginning of me filling in each segment.
I didn't cap much after this point, so from here it just jumps right to scp-173 in the back, and I do the class D guy a little later.
Here's' the semi-finished painting, I later decided to add a little gore and to crop it for sort of a widescreen affect. You can see the finished product above.