Publishing is a big, daunting business, and if you want to become a published author of anything-- fiction, nonfiction, children's books, genre, whatever-- you need to know a) how publishing works and b) your market.
After five years, I'm still learning. Learning is good, and if you really want this, you need to do a LOT of research.
So where do you start?
1) General questions/Query writing. One of the best websites for learning about writing, publishing, and how the business works is www.absolutewrite.com/forums Set up an account, and check it out. It is a massive website filled with writers, both published and aspiring. There are often agents and editors on that forum to answer your questions. They also have a Share Your Work forum which is password protected. There other writers, and sometimes agents, will help you craft your queries. They have step-by-step breakdowns of how to construct queries and synopsis's, as well as examples of those that have succeeded. (Also: Use google to find other writers forums. Find people who know what they're talking about, and ask them questions. Remember: there are no such things as stupid questions.)
2) Research agents. My best advice for researching agents (how to contact them, dos and don'ts, what they like, ect.) is to go to www.agentquery.com You can filter agents based on what they represent. Find agents who sell books similar to what you write, and look for any blogs they might have. Not every agent has a blog, but many do, and they have a lot of seriously valuable information. Reading blog posts will help keep you from making simple (but embarrassing!) mistakes.
3) Bookstores are your friend. Read, read, read books from the market you intend to sell in. Before you start sending out query letters, try to read 50-100 books in the same category you want to write. Get a feel for what others are putting out there, and what editors are buying.
4) How-to books. How-to write books are great. I'd highly suggest On Writing by Stephen King, The Breakout Novel by Donald Maass, and if you're interested in indie publishing, the book How to Become a Famous Writer Before You're Dead by Ariel Gore is WONDERFUL. Unfortunately I gave away my copy, but she has a lot of great ideas about self-promotion, and the voice all the way through is really wonderful.
5) Write, write, write. Constantly teach yourself about the English language. Learn how to properly use things like punctuation, increase your vocabulary (this can be achieved by reading more) and always try to invent new and better ways to phrase your sentences. This may seem like really elementary stuff, but you should always try to improve your basic skills. I've been writing novel-length stories since I was 12-13 years old, and I'm still searching for new ways to describe things, or find words that sound well together and invoke the senses. Words are the building blocks of stories. They are your tools, my author friends, so learn how to use them properly.
If you follow these steps (and be polite to people!) then I assure you, you'll have agents and editors knocking at your door in no time. :)
So get to it!