Collect and save as much documentary material as you can, even if you do not plan to start writing right away. Save old journals and diaries. Find or create a family tree so that you will have all the names and dates you need at hand. Look over all of your notes and decide which years of your life you would like to cover.
Break the autobiography up into sections that represent chapters of your life. Think about the themes or life-changing events that dominate each: coming of age, experiencing grief, or perhaps your journey to becoming a business owner. In writing about the events, make them informational while still being true to yourself, so your family and others will feel what you experienced.
Consider your target audience before you begin working on your first draft. Ask yourself if you are writing for children or adults. Use the right vocabulary once you have decided on your audience.
Keep the length of your finished piece in mind. This will help you decide how many pages or chapters to write on a single event.
Split your autobiography into parts. If you are writing about the last forty years, for instance, separate the information into sections such as work, family, outside relationships and pleasures.
Write in chronological order, when possible. Note that you can jump back in time to explain something that happened later on, but your focus should be on the outcome and the journey there.
Finish the autobiography by writing about where you stand presently in your life and the goals you may have reached throughout your life.