Writing about your life is important because it gives you a chance to reflect. Journaling is one of the main practices that therapists recommend for promoting mental health. It helps people manage anxiety, cope with stress, and deal with depression. When you maintain a journal and you go through your previous entries, you witness your memories without distorting the reality. You see your progress. You remind yourself of the important things you forgot.
Many people cannot resist the temptation to tell as much as they can, but a longer piece of writing doesn’t always equal a better piece of writing. For whatever reason you are writing the autobiography, think of the person who is going to read it. Imagine you were an admission officer or the judge in the scholarship committee, and you have to choose from hundreds, if not thousands, of autobiographies. At some point you will hate people who prefer to write long admission essays and autobiographies. There’s also a good way to check whether your writing is interesting or not. Give it to one of your most impatient friends, who prefers short articles to books and long stories, and ask for their opinion.
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.