I’ve written about this before. When you don’t know what to write about, and force yourself to write more, you find out who you are. (Or draw. Or make music.)
Create every single day, run out of your best ideas, drain the swamps of wit and dive deep into what’s left. It’s like reading the tea leaves in an empty cup, what will you learn about yourself? Once the burden of a good idea has been freed from your brain bandwidth, what’s left?