Just to get the aliases even shorter than the standard git config way mentioned in other answers, I created an npm package created a bash function on githubmingit (npm install -g mingit) so that most commands would become 2 characters instead of 2 words. Here's the examples:
g a . // git statusadd . would transform to
g b other-branch // git branch other-branch g c "made some changes" // git commit -m "made some changes" g co master // git checkout master g d // git diff g f // git fetch g i // git init g m hotfix // git merge hotfix g pll // git pull g psh // git push g s // git status and other commands would be similarly short. This also keeps bash completions. The package adds a bash function to your dotfiles, works on osx, linux, and windows. Also, unlike the other aliases, it aliases git -> g as well as the second parameter.