Record your own name & vital information, then your parents information. Move on to your grandparents & so on. Write down what you know & ask family members to fill in anything you have missed.
Get yourself a pedigree chart (ancestor chart) & start filling in the names. I suggest using a pencil as you may need to make a few corrections as you go along.
www.misbach.org/pdfcharts
http://genealogy.about.com/od/free_charts/