Face your fears
If you are out of ideas on what to write about, write about your fears. Are you afraid of wasting your life doing stand-up comedy without ever being discovered? Good. Joke about it. A lot. Do it well enough and long enough and you just might end up being discovered. I've always believed that before you can laugh at anyone else, you must laugh at yourself. And there's no better place to start than all those things you're afraid of. Because once you laugh at them, they're not so scary. They are just plain funny.