Choose a theme to give your autobiography a competitive edge. For example, an "academic autobiography" detailing your journey into academic adulthood or the story of your progression through your chosen area of study will demonstrate the importance of academics and learning in your life.
If you don't opt for a themed presentation, think through the points you want to include. This autobiography serves a specific purpose, so include points that emphasize why you are suited for your chosen program of study.
Write an outline as you would for any writing project. This will help you focus on the writing when you are ready to begin.
Include a variety of information in your autobiography. Detail a difficult situation and explain how you overcame it and what you learned. Write about a time when you experienced a turning point in your personal, academic or professional life.
Invite as many people to read your autobiography as possible before submitting it. Don't underestimate the significance of proofreading written work.