If I ever start at a new job where I'm given a new Mac I always set up these aliases. I'll list them with their output then at the end provide a gist of them you can add to your own aliases.
If you're on a Mac with OSX then you will find your aliases in ~/.gitonfig
You can add aliases with the following example:
$ git config --global alias.co checkout
Without further a...oh sod that cliche. Here's my aliases: