Stick to informal language, unless it’s absolutely necessary to use formal terms. Instead of “utilize” you can just put “use”. Focus on simple language, with one or two syllable words. The only time you should be using higher level language is if you are using scientific terms or describing a technical process. Even then, you should be writing for the average reader.
If your writing is atrocious, or if you just need some help getting your thoughts in order, consider hiring a ghostwriter or a professional personal historian. Celebrities do it all the time. There is also a software that allows you to type your answers into a template on your computer, thus solving the problem of less-than-perfect handwriting. Many people also choose to type directly into an online template.
“I was born in 19XX year, I entered school N…” Would you read that if you had a choice? Most likely not, especially if you already have read a dozen biographies which star with the same phrase. Yes, an autobiography is a formal piece of writing. But here, it rather means that you are not allowed to use slang and colloquial language, instead of following a specific pattern of writing.
It’s possible that writing your life story could be therapeutic, offering closure on some not so bright spots of your personal history along with emotional and psychological healing. Maybe your life was just a circus act from the beginning and is funny. If writing your life story touches you while you are writing it, think about all the people you can touch when they read it.
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.