I will add to this interesting discussion, somewhat snarkily, that a lot of people are in love with the IDEA of being a writer, as opposed to, you know, the actual writing.
I crank out the prose. I send stuff out. Ninety-nine times out of 100, it's a rejection. So far, I have three short story acceptances in magazines that you could maybe find in Borders -- which makes me a borderline professional. I am in no danger of quitting my day job.
The average advance for a first novel is about $5000 -- many people get less, a few of the Stephen Kings of the world get much much more. $5000 ain't a quit-your-job amount by any stretch of the imagination.
By about the fifth novel, assuming decent sales, you're at something like $20,000 per book, MAYBE. I live in California, in the Bay Area -- ain't nobody quitting their day job to go live on $20,000 a year -- and even if it's all you do, it's uncommon to write, critique, rewrite, revise, rerewrite, edit, rererewrite, proofread, polish, and sell more than one book per year. Most of the people you see on the shelves at Borders have a day job, teaching writing or English or whatever.
So the line between professional an amateur is at once both thinner and thicker than one might believe. The pros don't necessarily do nothing but write, unless they're very fortunate and have bestsellers and make well above the average for their work.
What the pros DO do is write something, take it through a critique process, rewrite, edit, and send it out. They don't:
* Complain romantically about how "I have too many ideas, and as soon as I start one thing, some other REALLY COOL idea comes up, and I have to drop what I'm working on to start that."
* Tell everyone about their story idea and never actually do it.
* Write a rough draft, post it on the Internet, and declare themselves a success.
* Write it and then hide it in their drawer for all eternity without ever revising it.
* Write it, revise it, and then not send it out because it would hurt their feelings too much if it got rejected.
* Say that they'll write once they retire (To which my standard response is that I was considering becoming a doctor once I retired from writing because, you know, I like medicine, I'm sure I'd be pretty good at it, I like the idea of making people feel better...)
ANYWAY.
In my experience, the ones who talk about intangibles like talent are the ones who don't actually write enough -- but that's just my experience. If you sit with your butt in the seat and don't get up until you've finished scene x, you're gonna be a better writer than when you started. Writing, critiquing, revising. Can't make you great, but can always make you better.
-Tacky