I've been forcing myself to get better around the edges. I'm forcing myself to pay more attention to the little things that I use, but use very inefficiently. One of those things is Git. Here are a couple tutorials that are really helpfull.
Ryan Irelan's Git Tutorial is a basic introduction to Git. Ryan does a really well paced walkthrough of the fundamental use of Git and some of the nicer Mac apps for Git. It's $15 for an hour of training. Not cheap, but not expensive either. I thought it was worth it.