A few tips on pursuing a career as a professional writer (because that's what you seem to be looking for, considering your second line there):
Tip #1: Be Realistic
I'm going to sound intensely pessimistic here, but I just want you and every other aspiring-to-be-published author here know the truth about what it's like trying to go through the system. (Personally, I haven't been successful myself, but I've been trying to work for the industry for literally years.) The first and foremost thing you'll want to know is that every publishing house gets thousands upon thousands of manuscripts a year. Out of that, the larger publishers like Random House might put out only about 300k titles annually. That might seem like a lot... until you look at it a bit closer.
Most of those titles will be non-fiction.
Speciality houses (e.g., those that publish mostly or exclusively fiction) might put out a higher ratio of novels, but they'll probably accept fewer manuscripts on a whole. The ones that they do accept are usually the ones that sound like they'll make the most money because they're aimed at a particular audience or just happen to advertise themselves well in the cover letter, which I'll get to in a moment. (So, basically, it's like getting an audience for fanfiction, only money's involved.)
Now, the point here is two things:
1. Getting published is a matter of patience, determination, and insane amounts of luck. You will most likely be rejected fifty times before you get someone to say, "Well, maybe." And that's if they don't just up and say, "Your manuscript isn't publishable, but here's a page of notes that should help you make it somewhat better."
In other words, don't expect to be published the first time you submit your work to a publishing house.
2. Presentation is a huge key to getting published. Proofread your manuscript before submitting. Learn how to advertise your fic. Work hard at making your novel seem like something they'd want to read, or you'll end up getting it dumped in the outbox.
Tip #2: Writing =/= Full-Time Career
That is to say, if you're a new writer, don't make expect to make it your full-time career. It's extremely rare that someone who's new to the writing industry will put out a book that becomes immensely popular overnight. In fact, out of all the authors that pop up each year, only maybe 1% of them actually gain the kind of popularity that lets them live off their royalties.
Writing, like every other form of the arts, is a part-time career. Most writers (even well-known ones) will actually hold a job or two while writing or publishing because, well, their books just don't pay the bills that much. This is especially true for new authors, especially if you don't get picked up by a major publishing house. Only a few people might buy your books, which means you end up with a tiny paycheck. (This is also in part because if you're an unknown author, unless your book happens to be something revolutionary in one way or another, no one will know who you are, basically.)
Of course, if you're a dependent (read: not yet old enough to pay your own bills), then most likely, this point is moot. However, yes, I'd hate to say it, but don't expect massive paychecks from your writing.
Tip #3: Learn the Industry!
There's a certain process every novel has to go through to be published. I'm not talking about proofreading or anything like that. I'm talking about assembling a cover letter, or a letter that states that you want your novel to be published by such-and-such company and that they want it to be published using their resources, too. I'm also talking about sending your novel to the correct publishing house. There's literally millions of different publishers worldwide. The first key is to know something about them in order to help get them interested in you. For example, if your novel is a fantasy shindig about child wizards, you don't want to send it to a company that publishes exclusively romance.
My advice here is to pick up a copy of Writer's Market. It's a massive Tome of Doom, but it's also the resource most recommended for published authors by published authors. Not only will you find listings for every single publishing house and magazine still in existence, but it also provides guides on how to write cover letters, how to go through the publishing process, and other things published-authors-to-be need to know about the industry. They say a lot more stuff than I could possibly offer.
Tip #4: Get an Agent!
A misconception a lot of kids aspiring to be published authors have is that they can just submit their work to a publisher without having to go through a middleman. This isn't the case nowadays.
A literary agent is basically like a talent agent for movie stars. They take a look at your work, scope out the best places for it to get published, advertise the novel for you, and negotiate a contract with your future publisher. In other words, they take care of all the nasty details so you can just worry about writing.
They're also an immense help for two reasons:
1. Most publishing houses don't accept unsolicited manuscripts. That just means they don't accept novels sent in by the authors themselves. The reason why is because an agent functions as a first filter. Agents are experienced talent representatives, so they know a well-written story when they see one. As a result, publishers will be more willing to accept a manuscript backed by an agent because it basically already has a first approval.
2. Contracts are evil things. You could get screwed over by a publisher pretty easily (especially since printing isn't exactly free). Granted, you can get screwed over by an agent, too, but that's not as bad as getting messed up by a publisher. With publishers, you're messing with copyright laws and a whole list of other laws that could cause serious problems, so you'll need someone who understands contracts and the industry well enough to guide you through the mess.
Tip #5: Of course, the usuals.
Proofread, create an interesting story with deep characters, that sort of thing. My advice would be to consider holding off on trying to get published and focus more on practicing first until you're sure you've got something good together. Post other stories you've penned to writing communities like this one to get feedback and shape your writing style. As I've said earlier, you're in fierce competition with a lot of other people who want to be published as well, and on top of that, there's only so many people who get a book printed (let alone recognized enough to live off their royalties) each year. So, you'll want to do your best to make sure your stuff is as perfect as you can get it.
In short, there's a lot that goes into publishing. I'd suggest starting off by picking up Writer's Market to get an idea of what kind of industry you're trying to get into if the above doesn't give you enough of a glimpse as it is. But mostly, it's not a quick and easy process. I'm not saying give up right now. I'm just saying you'll want to be aware that it's going to take a lot of research and effort and pain and waiting on your part to get the results you're looking for. It's possible, but you just have to be prepared to work on it.
But hey, if you really want to get something published, there's other options that are slightly quicker than an entire book through the conventional publishers:
1. Self-publishing (e.g., Lulu). Warning: You might not see a paycheck from this, especially if no one knows who you are. People are more inclined to buy books through sites like Amazon or through physical book stores like Barnes & Noble. However, self-publishing means you have to advertise your work yourself. If you have a physical book, you'll need to buy shelf space to display it in a store, and if you're online, then you run at a risk of having no customers because they don't know you exist. You'll really need to know a bit about business to really get off the ground -- or at least have a nice number of fans already lined up to buy your work.
2. Magazines. Do searches on literary magazines and webzines that might accept short stories of yours. Sure, you might not get a novel out, but it's something. Agents will be more willing to work with you if you've already been published anyway. As a warning, you're paid by the piece with most magazines, so you won't exactly make a living off of this method, either. Unless you're insanely savvy.