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.
You may wonder how to start an autobiography introduction. The answer is simple: the same way you start other essays’ introductions. The main purpose of the introductory paragraph is to grab the reader’s attention and present the idea and theme of your writing. Don’t make the first paragraph too long: between one and three sentences are enough to compose a regular introduction. Try to provide readers with a general portrait of yourself, so they will know more about the main “hero.” Mention your age, significant personal qualities, and principles of worldview. You can also add some details about your appearance in order to make your story more vivid.

We told you how to start. When you get through that point, it will be easier to continue. You will follow the plan and you’ll keep developing it. At one moment, you may even notice that the words are pouring themselves out. You’re finally expressing the things you’ve been carrying inside for so long. That may be a torturing process, but it’s also liberating in a strange way.

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.