Show, don't tell. Engage your reader by showing them a specific process or scene, rather than narrate directly to them. For example, write a scene that shows the reader how you discovered your mother’s letters from her family in Poland after her death. This will give the reader key information to help move the story forward, without telling them in a long, uneventful passage.
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.
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.