Brainstorm an important life event for your topic. it could be a single day where something important happened, or it could be an experience that lasted over your summer vacation. describe the subject you plan to develop in your memoir, including any details or aftereffects it might have.

here are some steps for brainstorming:

create a list of words or phrases that you can use in your memoir or an idea map that shows how different parts of the story are connected.
choose a perspective to maintain while writing the memoir. do you want to describe a topic in detail or simply mention certain aspects? do you want to celebrate something like a cherished memory or accomplishment or admit to a flaw in your reaction to something? or do you want to observe some part of daily life so closely that you find something surprising in it?
check that your subject will allow you to have something significant to say about it.