My nephew lost a tooth recently, and inspired this particular piece. Full size -here-. Now, even though this started out as a quick sketch/joke image, it quickly turned into a very fun exercise in edge control and limiting myself with layers. I've always had a bit of an addiction to layers in Photoshop, and have recently been trying to work on single layer images to force myself to really consider the image as is, rather than saying to myself, "Oh, I'll just fix that later on another layer." Invariably, that particular vein of thought is forgotten, and the image looks sloppy. That, or I'll have to look through many many different layers to find the one that has the thing I'm trying to fix on it. This technique however is very simple, and I've used it successfully before on both a Jelly-Fish and a Mermaid (NSFW). Working with only black and white, and a brush with opacity and flow controlled by pen-pressure, I use this to paint in the lines, and then use the eraser to sculpt in the line by erasing from the outside in.
A collection of sketches,