Ira Glass, from a Lifehacker interview.
Don’t wait for permission to make something that’s interesting or amusing to you. Just do it now. Don’t wait. Find a story idea, start making it, give yourself a deadline, show it to people who’ll give you notes to make it better. Don’t wait till you’re older, or in some better job than you have now. Don’t wait for anything. Don’t wait till some magical story idea drops into your lap. That’s not where ideas come from. Go looking for an idea and it’ll show up. Begin now. Be a fucking soldier about it and be tough.