From a Ted Chiang interview:
For me, it is about identifying the things that you find interesting that no one else finds interesting. That’s one way to view your job as a writer: It’s to tell stories that no one else is going to tell unless you do. I feel like there are a lot of stories that we read that anyone could have told. There are books that you read, or movies or TV you watch, and you feel almost anyone could have written them.
There’s also a good Annie Dillard quote that’s mentioned in the interview:
You (writers) have been sent here to give voice to your own astonishment.
I hadn’t thought of it this way before, but it seems to be a decent goal, I think. Write what only you can write. And I would broaden that to: Make what only you can make. I’m trying to figure out what that means for me, both for writing and for everything else.