Write down information about yourself. This information will include vital statistics as well as memories of your family history. Complete a pedigree chart, and talk to elder members of your family to help you fill in missing information.
Use your chart as a guide to help you work backward, to your parents, then grandparents and so on.
Remember, start with yourself, then work backward.
So what do you need to know about each person in your tree?
If you are gathering information about a deceased relative, note when, where and how the person died.
Each of these facts should be documented.