You have your novel finished. Now what?
You have lots of options -- traditional publishers, small presses, ebook publishers, vanity/subsidy and self-publishing.
I'll talk about each form of publishing with some pros and cons to consider so you can decide which fits you better.
Traditional publishers are the publishers you find in bookstores. In US publishing, many are based in New York City. Some of these publishers of genre/popular fiction include Tor, Pocket, St. Martin, and Kensington.
The major advantage to these publishers is distribution. Their books are carried by all the major book chains and distributors so anyone can walk into the neighborhood bookstore and buy or order your book.
The better the distribution, the more books sold.
They will also give you an advance on your earnings and cover all the costs of creating the book itself including editing, the cover, and the printing.
Authors published this way are on the top of the author pecking order.
The major disadvantage is competition. You will have an uphill battle to gain a coveted slot in a publishing schedule and your competition will include many published authors.
In some markets, you'll need to get an agent even before you begin the fight for that slot, and this is an equally difficult and slow process.
Another disadvantage is lack of control. You will have almost no say in your book's title and cover. More often than not, you will also be required to change some of the book's content.
Pigeonholing is another problem. You must write to fit the current trends in popularity. It's a rare book that can be totally different.
Small press is really a small version of the traditional publisher, but rather than being owned by a conglomerate, it is owned by individuals. Many are niche publishers specializing in a particular market like regional mystery or paranormal romance.
Some have the advantage of good distribution through book chains and distributors so they can be found in bookstores, but others do not. It will be much harder to find your book in a bookstore, but it should be available for ordering.
All the expenses of editing, cover art, and printing are covered by the small press, and some offer advances on earning which are usually much smaller than the traditional publisher.
The amount of author impute in the publishing process ranges from none to a great deal according to the individual press.
The disadvantages include poorer distribution, the vagaries of the how each runs its business, and the inherent risk of working with a small company where an owner's illness or family problems can stop the presses.
Subsidy/vanity presses and self publishing in paper.