Begin by writing your name in the middle of the page and drawing a circle around it. Don't make it too big, because you'll want to save room for brainstorming ideas.
From the circle, draw five to six lines branching off of your name circle. Try to make them evenly spaced around the circle so that you will have enough room for topics and stories. Draw circles at the ends of the lines for the categories you choose to write about.
Brainstorm five or six main categories that you want to address in your autobiography. Make the categories broad enough to include a number of scenarios. Here are a few examples: family, school, childhood, work, friends and relationships.
Write your categories in the circles that you drew at the end of Step 2. If you find yourself with more than six topics that you want to write about, that's okay. You should simply create another diagram with those extra categories. If you add too many categories on one diagram, there will be very little room for further brainstorming. Color-coordinating and/or numeric labeling is a good idea if you have a lot of topics to address.
Branch off from each category circle four to five times. If you want to be more detailed, you can make these next items subcategories or topics. Otherwise, you can choose stories within the general categories. There are a lot of stories to choose from, so pick ones that mean the most to you and begin writing the first draft of your biography.