observational pen drawings

I do a lot of observational drawing. They're fun and they keep the pen moving. When I draw out of my head, I mostly stare at the paper blankly and get a nosebleed from thinking too hard about what to draw. Observational work is fun because there's no shortage of things to draw. You get lots and lots of practice and it prepares you for when you do have to do imagination drawings. This discipline informs the other. So carry your sketchbook with you everywhere and draw everything in sight!