Just as we all have histories (or herstories), we have geographies. Think of every place you have ever lived, and write a story, using the location as the main character (or omniscient narrator).
I grew up in a modern-day, Tennessee Williams play. Draw upon your background, for no one can tell it like you can. https://sarahleastories.com/2015/11/10/poem-a-day-writers-digest-challenge-7-theme-simmer-down/
We are all the product of our existences, experiences, and memories—we all have something to offer. https://sarahleastories.com/2016/03/01/writers-digest-wednesday-poetry-prompt-342-theme-blank-ways-to-blank/
Just as some remember where they were during historical events, for me, every memorable book I’ve read (good and not so good) has a memory attached to it. https://sarahleastories.com/2018/02/20/influences-on-my-early-writing/
Great writers practice the art of self reflection.
Our life is a timeline. If you have a tough time filling in the gaps, write about the dots. https://sarahleastories.com/2016/02/04/writers-digest-wednesday-poetry-prompt-339-theme-anticipation/
How did you meet those who became significant characters in the play that is your life? https://sarahleastories.com/2015/12/04/writers-digest-wednesday-poetry-prompt-330-theme-shopping/
The dust of time and even the subtle shifts of our perceptions can alter our memories. Play around with different accounts from siblings, friends, et cetera.
Sift through old correspondence. You might find a “found poem” or a lost memory. https://sarahleastories.com/2018/01/28/childhood-memories-pen-pals/
The best thing about writing what you know is that the research is already in your head. http://www.bryndonovan.com/2016/07/05/100-prompts-for-writing-about-yourself/