Have you ever wondered how you can become a Personal Historian? Here is a quick explanation for you: http://tinyurl.com/yelbsu7 in Wiki. There is also a wealth of excellent information on the website for APH - the Association of Personal Historians: http://www.personalhistorians.org/, of which I am a member.
The important thing is to start writing. And who better for your first client than yourself or someone you already know? You'll be amazed at how much more you will learn about yourself and them.