Sometimes in composition class, when I have been confronted by someone who simply cannot get the first word written on paper, I give the following advice: Say your essay into a tape recorder and then write it down.
Remember that you own what happened to you. If your childhood was less than ideal, you may have been raised thinking that if you told the truth about what really went on in your family, a long bony white finger would emerge from a cloud and point to you, while a chilling voice thundered, "We *told* you not to tell." But that was then. Just put down on paper everything you can remember now about your parents and siblings and relatives and neighbors, and we will deal with libel later on.