So how do you go about publishing? Here are some tips that I hope are helpful:
Look at who is publishing the books you enjoy. Say, for example, Viking publishes a lot of the books you read and like, then start with them first. And as a side note to that, always start out up at the top. That is to say, don't settle for a no name publisher.
Agents: going through an agent is one possibility. The agent functions as another editor before you send it off to the actual publisher. The agent can get your book into publishing houses that wouldn't otherwise look at your book. You should never pick an agent where you have to pay money upfront. If that is the case, then just walk away. One negative side to an agent is that they make roughly 15-30% (depending on what you both agree on) in all the royalties--forever!
Contracts: you can get a contract lawyer. Royalty is the amount you get back per a book sale. In general, you usually get a 10% royalty. Your advance, the money they pay you before any sales are made, is against your royalties; meaning, until your book makes up your advance in royalties, you don't get paid anything more.
Editor: think about your editor.... Look for editors who publish books you really like. Develop trust (i.e. never miss a deadline!). Pick an editor who will push you. Editor's like people who engage with problems (and don't always respond in a slave-ish, minion "yes sir" sort of way). Editors want you for the long haul, they want you in their stable. Develop a collaborative relationship of trust.
What you can expect...
It is your obligation to help promote your books. Go to book signings, conferences, and so on (I mean they did just spend a quarter of a million getting your book out there).
At any point, when the publisher asks you to put out your own money, that is a red flag--say no. Be hard nosed. You know how much you are worth, so you know what a reasonable fee for your time is.
If you are not going to publish through a house, then there are literary magazines. These magazines are hungry for matter. Most have very high standards. Write a cover letter that shows the title of your piece you enclosed, a brief sentence saying what your piece is about and why it fits the particular magazine, and a brief sentence showing your history of publication. And, in general, you should always maintain copyright.
Hope some of this helped.