So You wrote a book...now what

Here's my brief opinion on the matter: Remember, I'm no expert on these things.
The answer to the question depends on your writing/ publishing goals. Self publishing is a valid option and shouldn't be overlooked, but if you're hoping to sell a gazillion copies you might want to try the longer, harder traditional publisher road.
No matter which option you choose, be sure to proof and reproof your book and have others proof it for you. Then, research carefully all options. There are tons of self publishers out there and most of them are crooks. A good starting place is predator and editors (google this, it'll come up right away). The first two agents I queried said that I was the world's best writer and they wanted to represent my book...well, good thing I found out they were crooked b/f I committed money, but many aren't so lucky so take notes, people.