Saw this article on Deviantart. Figured I should post it up for anyone who hasn't seen it. I Agree with a lot of what the writer says. Forcing yourself out of your comfort zone is a good way of improving. if you're not so good of a background artist, start drawing backgrounds. if your coloring is a little weak start experimenting with colors. Definitely use references if you need to. I can't stress that one enough. It's not cheating or a sign of weakness to use references. That falls into the whole idea of working smarter.
anyways that's enough ranting on my end. I'm about to pop in Star Trek.