Write a rough first draft. You may feel pressure to write and rewrite every sentence you put down. But part of writing a memoir is writing an honest account of a pivotal event, in your own words and with your own style. Avoid putting on a “writer” voice. Instead, don’t be afraid to write like you speak or talk. Include slang and any regional vernacular. Make your story sound like it is coming directly from you.
Develop a central theme, main idea or thesis that clearly explains the purpose behind your autobiography. For example, your theme might be about how you overcame obstacles to become a stronger person, or it might explain why a particular passion -- such as mountain climbing or rescuing animals -- is so important to you. Back your theme with details and background information about your life experiences. For example, you might explain that your dad is in the military, so you've had to learn how to adapt quickly to new schools and unfamiliar environments. Or, you might discuss what it was like growing up in a poor, single-parent home, but how your family was always willing to take in injured or stray pets.