I've been developing some new video-walkthroughs for lectures. They're aimed at people who are new to digital painting/concept art, so I started with the basics. The first couple of videos are based around thumbnailing and generating composition studies. One set of designs is done traditionally with pen and a sketchbook. The other set of designs are done in Photoshop. I set some limits within Photoshop: I could only use one brush (the default Hard Round Brush) and had to be very minimal with the number of values I used.
These two images are the final pieces and the links to videos