Write an outline. Refer to any journals or diaries you may have kept along the way. Without a journal or diary, take time to reflect on your childhood and the key elements of your childhood you want to include in your autobiography. As interesting as your childhood may be to you, not every incident in your childhood will make good material for an autobiography. Create a simple outline with chapter headings to give you an indication of the ordering of the events you choose to cover. Organize your chapters in chronological order. You can create chapters around strong events in your childhood -- or time periods, say from first through third grade.
Introduce yourself and the main purpose of your childhood autobiography. The main purpose, or the reason you're writing your autobiography, is particular information that provides value to a reading audience. If you are a recovering addict and telling that story, this is what you will talk about in the first chapter. If you are simply writing a childhood autobiography because you feel you've led an above- average life in some way, state some of the situations that point to this. Be brief (one or two chapters). You will go into these experiences later, in more detail.
Write two or three chapters going into detail about the basics of your childhood, including when and where you were born, who your parents are, and some of the main places you have lived. This is laying a foundation that will establish you with your readers. You are the main character in your autobiography. Like any type of writing, you want your readers to understand and sympathize with you.
Write in such a way that events of your childhood lead into one another. From the chapters detailing your basic information, recount the events of your childhood leading up to the main purpose of your autobiography. Many writers will remain chronological, which tends to make sense for an autobiography -- but that doesn't mean you can't relate events out of sequence. Do so if it helps to establish a particular part of your childhood you're writing about.
Decide where to end your childhood autobiography. Will it be when you reached a certain age -- say age 12? Will it be when you first entered high school? Will it be when you started your first job? Your first boyfriend? When you reached age 18 and graduated from high school?