Link your public ssh key on your github account:

cat ~/.ssh/id_rsa.pub

Clone your repo:

git clone git@github.com:<username>/<reponame>.git

For example:

git clone git@github.com:sheanmassey/sheanmassey.github.io.git

See diff of unstaged changes:

git diff 
git diff | vim -

Committing all modified files:

git commit -a -m "this is my commit message"

Pushing your changes to github:

git push

You'll almost always branch from master. Branching allows you isolate a "set of changes". I like to branch on every new feature or fix. To list your branches you use:

git branch

To create a new branch use:

git branch my-new-branch
git checkout my-new-branch

git checkout -b my-new-branch