I found a great cartooning book by Jack Hamm, from the '60s, for a few bucks at a used bookstore the other day. It's filled with pages and pages of exercises for cartoonists and illustrators and it was perfect timing to practice with my newest brush pen. This is one of the best books I've read. And I've learned quite a bit more already about how personality can be conveyed with a brush and a minimum amount of lines. The beards I drew in my Moleskin mini suggested some characters right away and proved Professor Hamm correct.