It's "the look", mainly.
Every writer knows that look. It's the same look that people give children when they say they want to be an astronaut when they grow up. The look that says they want to chuck you under the chin and say, "Reach for the stars, champ!" while they're thinking, "You're going to be a mid-level executive in a factory that makes hinges and other door parts if you're lucky."
So, what you do in the meantime, if you're really lucky, is talk to other writers. Other writers know "the look". Other writers don't believe you're bound for a hinge factory. Other writers, if you're really, REALLY lucky, will encourage you every step of the way and on the day when you're finally able to announce that all of your hard work's come to fruition, will celebrate your victory like it's their own. (Can you tell that I found that group of writers?)
Three years ago, I started working at The Curious Iguana, an independent bookstore with a global and social justice focus. During my first month, I bought this button, because I had faith. I had faith that I could eventually write something worth publishing.
But I also have faith, that as I begin the revision process (my first editorial notes also came through yesterday) that I'll be up to the challenge of turning a promising lump of coal into a diamond.