We tend to write what we know. Isn’t that what all creative writing teachers tell their students? I know mine did. Even that is difficult, since we’re often afraid that what we write might be misinterpreted by those we know, or that people will assume what we write is in some way autobiographical. One thing all writers need is imagination and guts. We need to write and not be afraid of what others will think. We need to have faith that the stories we’re telling will inspire imagination in others and what we had in our head when we wrote finds its way into the hearts and mind of others.
Try writing about something you know nothing about. Write about a profession, a place, a person or anything of which you have little or no knowledge. Once you’re written your story, check a few facts if you need to and see if what you wrote make sense or is plausible.
Try another experiment, write about a time in history outside of your own lifetime. Make up the people, the scenery, the customs and clothing. Make it a real time in human history, but use only what little you know from reading, TV and most importantly, your imagination. See what comes out.