Q: How often should I checkin code into github?
A: More often is better than less often, if you write a lot of code, do it at least 2-4 times a day.

Q: Should I branch/fork?
A: branching and forking is there to help you better organize your code by feature. If you are working on an open source project, you will need to fork it first so that you have access to checkin code into it. After you forked a project, you may want to create branches for different features that you will be working on. If you are part of one organization where you have access to the repo, you may want to forgo the forking and go straight to branching. This is a decision that each group needs to make.

Q: Can I work from master?
A: Yes you can, but you probably should not! Think of your master branch as a golden copy of your code. Merge to it after you thoroughly tested your new features or bug fixes.

Q: What if command line scares me?
A: Use GUI tools built just for you!  There are lots of them out there, my favorite one is: http://mac.github.com/

Documentation

While looking up some documentation for git, I came across this awesome cheatsheet:
http://ndpsoftware.com/git-cheatsheet.html

Try clicking on it!

You may be aware of github documentation, but do visit git docs once in a while as well to get very clear and detail answers to all your git questions:
http://git-scm.com/doc

-eglute