Git from the Bottom Up
A tutorial/reference that covers a lot of detail about git.
git best practices
Article relating to best practices as a git user. Some gems in here.
Deleting Git Branches with Magit
As this article says, I've always tended to drop down to the CLI to delete a branch, and ensure it's cleaned from the remote, etc. Somehow I'd never picked up on the fact that Magit just handles this. And of course, it does, Magit does so much!
Write yourself a git
Learn how git works, by writing a git.