Begin by taking a circular object (a CD works well) and drawing the moon in the upper center of a regular piece of copier paper. This will remain unpainted.
Next draw a tree extending from the bottom left corner to the upper right corner. Make sure that the tree trunk and branches taper at the ends.
An animal on a branch is a nice option. (A few students added bats hanging upside down.)
Paint said tree and animal with black tempera paint. Let the black paint dry. (Jeff waited until the next art period.)
Using oil pastels, color the sky with night time or dusk colors.
Once the entire background is colored, blend the colors using your bare fingers in a circular or side-to-side motion.
Jeff actually got too much dark blue oil pastel colors on his (the top one), and when he began rubbing it, it made this swirly solar system design. It was a mistake, no doubt, but his students loved it and most of them had to work this astonishing accidental effect into their projects as well. Yay for accidents-- I mean experiments-- in artwork.