I recently had the pleasure of working on an illustration to accompany a lovely short fiction by Maile Meloy in the New Yorker.
The editor, Chris Curry, sent me the layout above and suggested a dyptic with two separate scenes.
I typically sketch until I have two or three decent concepts or until the sun is rising and I can't keep my eyes open. The three sketches above begun as very loose pencil sketches which I scanned and further developed in photoshop with a wacom tablet. After submitting these concepts, Chris suggested trying an eight-panel composition...
Sketch approved! One minor tweak to the first panel...
I usually do a quick digital color study before I jump into the final.
At this point, I turn the black lines of my color sketch faint yellow and print out the sketch on a tabloid sized piece of bristol board. The yellow ink, barley visible in the photo above, serves as my "pencils." I still use traditional media for inking: real brushes, nibs, and India ink. As you can see above, a fair amount of editing takes place during this stage as well.
Next, the color gets added back in digitally, and, presto.