While you might not remember every detail about a certain event, I guarantee someone who was there does remember. Asking family and friends for ideas or details of a certain situation can give you a completely different perspective of the event or time in your life. That perspective might prove to be invaluable in your writing. Be prepared; once you get a group of family and friends together to reminisce, you will be shocked at how quickly the ideas come and how one idea can spark another and another and another.
I think the first and best step to getting things out – but not necessarily writing your life story for anyone else to read – is to buy a journal. Start writing about your experiences and painful memories. It will hurt, but the only to get past the pain is to go through it. The more it hurts, the better it will be in the long run to process the experience.
Incorporate dialogue into your autobiography to make it more personal, recommends history professor Robert Gerlich at Loyola University in New Orleans. Consider including humor when it's appropriate. For example, if you're writing about how you got lost at Disneyland when you were 10 years old and how the experience helped you learn to face obstacles, problem solve and overcome your fears, you might write, "The attendant at Splash Mountain said, 'Are you OK? Did you get separated from your family?' I quickly replied with as much bravado as I could muster, 'Nah, I'm fine. My eyes are just wet from the ride.' I didn't want her to know I was crying."