I recently read about an artist who doodled on the back of business cards. I started this painting on a 3"x2" cardstock and did quick watercolor washes to give the base color. I like that the small size limited the amount of detail I can put into it. Then I pushed and pulled the values in photoshop. I've been into textured brushes lately and have a few favorites, but one in particular is the charcoal brush seen above.