The best way to begin the writing process of writing your autobiography is to break the necessary steps down. This way, you'll know what you have to do on a day-to-day basis in order to have your autobiography completely written in a designated amount of time. Combine both positive and negative aspects of your life to create your autobiography.
Think of your life's top positive moments. However, don't list too many; stick to approximately 10. Jot down notes next to them to remind yourself of details when you're ready to write. Next, write down your absolute worst moments, keeping this number less than the number of positive items you listed. Make sure to not just come up with the event itself, but also think of the emotions you experienced during this time. Try to connect the good times with the bad times, either by linking people or details, or figuring out similar learning experiences for both.
Speak with key players from your life, including both immediate and extended family members and friends. If possible, contact people who you used to be friends with, such as old college roommates, or even an ex-boyfriend or girlfriend if possible. This will provide an alternative perspective on your life and may open up creative doors you wouldn't have thought of otherwise. Ensure the people you interview understand you're doing research for a book you're writing; this way, you'll have their consent to publish things they talk about or direct quotes.
Create a schedule for when you want to have your first two drafts written. Try to put some space between drafts. If you write your first rough draft and wait a few weeks before working on it, you'll return to your writing with a fresh perspective. Revise your first draft and repeat the process, coming back a third time for a final revision. Once you're satisfied with your final copy of your autobiography, have one or more people read it. Make sure you choose people who you trust, whose opinions you value and who tend to appreciate the written word.
Writers tend to get their best work done when they're in a comfortable, quiet setting. Get ideas for types of topic to include in your autobiography by reading other autobiographies. This is a great way to determine which styles and topics you love and which you don't enjoy reading about and therefore won't want to include in your own book.