ONLY use this .gov site to complete your FAFSA!
Use this PDF as a practice sheet so that you know exactly what will be asked when you complete the online form.
Not as comprehensive as the Practice FAFSA above, but offers an overview of FAFSA sections and information needed.
If you have a question, someone else probably does too. Consult this list from StudentAid.gov (the official site!) for help.
Excellent guidance in multiple short videos from StudentAid.gov. Overview of the Financial Aid Process is very good, as are others.
Step by step video from the Road2College Blog.
Helpful by-section videos from the Khan Academy.
Wondering how FAFSA fits into the overall picture? This site from the National Association of Financial Aid Professionals has excellent explanations.