Your readers won’t be interested in reading the whole text of your autobiography if you don’t provide a good impression in the introduction. Convince your audience that your story is unique, original, and is worth their time. If you are going to write about an episode from your childhood, use a feeling of nostalgia to create a tight connection between readers and your own memories. Remember that all people are the same to some extent. We live through similar experiences every day, so you should use these similarities to make your writing attractive for the general public.
Once you have taken a look at your own life from an outsider’s point of view, you will be able to select the most interesting elements from your notes to establish a theme. What was the most interesting thing you came up with in your research? Was it the history of your family and your region? Here is an example of how you can turn that into a theme:
Organize what you've written according to cause and effect and action and reaction. Ordering events according to cause and effect is a natural process. Your car broke down, so you called a tow truck. That's cause and effect. You received a promotion, so you bought a house. Action/reaction happens paragraph by paragraph. He said "No," so you said "Why?" That's action/reaction. She set a wet glass on the table, so you placed a coaster under it, and remembered how your mother used to crochet pretty little coasters and starch them. That's action/reaction.
You should check your autobiographical essay for mistakes in spelling, grammar, verb tense, style, punctuation, word forms, etc. No matter how emotional or exciting your writing is, your readers will stop reading as soon as they notice the first grammatical mistake. An illiterate author cannot win the trust of the audience, so you should take this step very seriously.