For those of you also fantasizing about this wonderful dream, there are a few truths I've learned in the past few years about being a professional writer and how hard it really is to gain that sort of notoriety. These are things I've not only heard multiple times, but have found the most grounding when working toward my own dream. I'm not trying to discourage anyone from going for their goals, but it is always good to know the realities and plan accordingly. So here we go.
1. It takes a little more than just skill at your craft to be a successful writer. It take a good amount of "luck" as well.
It's the American ideal to believe that hard work will always get you where you want. However, sometimes a little bit of luck, and being in the right place at the right time, comes in handy and can open doors that your skill can then get you through. Planning for being at the right place at the right time is also important. If being published is something you aspire to; read, read, read. Know what is out there and what is popular at the time. Sure, your story might get picked up by an agent or publishing house and start a revolution in the genre, but the probability of that happening is very slim. Knowing what is popular and using that to your advantage can give you a foot in the door. If vampires are popular, you might have a better chance of getting picked up if something like that is in your story OR you find an agent or publisher that has a history of picking up those sorts of tales. This in no way means that you have to pander to the current genre quips, but at least knowing about what is going on in the publishing world helps.
2. Keep on trying, because you will get rejected a lot.
Rejection is going to happen. A lot. When we got to the truths portion of my senior writing class, my professor brought in his collection of rejection letters. It was very thick. I'm pretty sure if he dropped it on a small animal it would have needed medical attention. He'd even organized the letters by their level of politeness and rudeness. He read a few of them to us and ew, they were harsh. If your skills are up to snuff and you're really bent on getting that deal, you have to keep going. And listen. Listen to what people tell you about your writing. Sometimes you might need to work on something before you're up to the level that a publisher would be looking for in a sellable novel. It can take years to sell a novel and usually does. Don't stop believin'.
3. The money isn't just going to start pouring in. You'll have to keep your day job for awhile.
Barry Lyga has probably the best response to how authors get paid (something I didn't know myself). It's not an instant in and there's lots of hard work that goes into making yourself financially stable. There isn't much more I can say on the topic that isn't up there. Read it!
Those are really my big three. If you're looking for even more advice from ACTUAL professional writers, if you Google the question, there will be much more info than what I can provide. Keep on writing. That's the best advice.