A Guided Tour through the Fundamentals of Git
I highly recommend biting the bullet and reading through Pro Git by Scott Chacon (from Github).http://progit.org/book/It's about 200 pages but it really, really helped me internalize how git works. Each git feature/command is explained with a use case and a clear illustration of what's going on.The online version is free and it's available as a PDF, epub, and mobi.