The aim of such an essay is obvious: you need it to convince admissions officers to accept you into college. As a rule, there is a word limit specified in the instruction for applicants. Don’t confuse an autobiographical essay with your CV or resume! They have totally different structure and formatting. In addition, the essay is aimed at portraying you as a personality, not as a professional.
Be revealing. You don't have to be explicit, but it's important to reveal truths about yourself and your life in an autobiography. Don't let the book become a list of your accomplishments, with all the negative material carefully kept under the rug. Present yourself as a whole person, sharing talents and flaws alike, and your readers will be able to identify with you and hopefully root for you as they make their way through your story.
As is present in the biography of a person, your place and time of birth, your parents’ views, an overview of your personality, your likes and dislikes, and important events that shaped your life should always be included in your autobiography. This will give a mental picture of your life to the readers as a sort of backdrop to the main part of the story.
This is an extremely emotional and intimate type of writing. You share a personal experience with your readers in a detailed manner. Your audience should have an opportunity to see the event or person that you’ve written about through your eyes and understand your feelings. Any personal essay has two main aspects: the description of a particular situation and how it has influenced your worldview and life. Generally, the personal essay is the shortest form of autobiographical writing, along with the essay for college.
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.