There was this scene in a cartoon my son was watching where two kids wanted to be rock stars. They started writing a song but realized they didn’t have enough life experience to say much in their lyrics. So they went out and started doing a bunch of things to expedite the process. I laughed and my son asked me what was so funny.
Songs come from concepts, and concepts come from ideas. Ideas come from thoughts, and thoughts come from experiencing life. In the same way you can’t have happy accidents unless you’re actually doing something, you can’t have compelling thoughts, ideas, or concepts without having experiences that move you in some way.
If you’re young or you feel like you don’t have much to say, go do something. Travel. Read a book. Climb a tree. Put yourself in a new situation. It might seem contrived, but writers do this all the time. Ron M. Persing’s Zen and the Art of Motorcycle Maintenance. Eat Pray Love by Elizabeth Gilbert. Bon Iver’s For Emma, Forever Ago. These works and countless others were written by people forcing their creative hand into giving them material. You can do that, too.