Be revealing. You don't have to be explicit, but it's important to reveal truths about yourself and your life in an autobiography. Don't let the book become a list of your accomplishments, with all the negative material carefully kept under the rug. Present yourself as a whole person, sharing talents and flaws alike, and your readers will be able to identify with you and hopefully root for you as they make their way through your story.
If the project becomes too much for you at any point, remember that writing an autobiography takes time. Take the pressure off. Relax. This is your autobiography. You can make it as brief or as complete as you like, but don't expect to write it quickly. It may take years. If you want to finish fast, you might try the $14.95 Memorygrabber software I mentioned early. The publisher offers numerous free downloadable pages on their website, so you can decide if that approach will be useful or not.
Understand the memoir genre. In a memoir, you are the main character of your own life story. Many memoirists use the facts of their life story to create an engaging tale for the reader. Because you are relying on your own memories as source material for the story, you may end up describing things differently than others might remember it. The key is to write down things as you remember it, in the most honest way possible. Keep in mind memoirs are different from autobiographies in that memoirs should only cover certain key aspects of your life, not your life from birth until the present day.
“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.