Spit Paint Daily is a group on Facebook that does a daily art challenge. The challenge is to select a topic out of a few options and paint/draw it in 30 mins. They change the the topics everyday. It's pretty fun, great practice, and there are a lot of really talented people that participate, as well as beginners. Here are a few of my of my attempts, a lot end up miserable failures... ha.
"Tracks in the Snow"