OK, you've got your manuscript in hand. It is not your first draft or your second, but your well edited umpteenth draft. Now what? My suggestion is look for an agent.
Many people suggest sending straight to publishers, but I think that you should take at least 12 weeks and see if an agent is interested. They are your advocate and key to the publishing world.
Beware, they are hard to get. Many only take on one or two new clients a year, unless they're building their list. But it is worth a try. I'm always amazed at my SCBWI meetings when a first time writer stands up to announce their "good news" that they got an agent. Lucky ducks!
An agents return response time varies too. It can be anywhere from 24 hours to 12 weeks. So you do need to be patient. If you're an impatient person the publishing world is not for you.
So, where do you look? Here are a couple websites to help you out:
It is a free database of agents.
Association of Authors' Representatives
The agents that are members of the AAR must abide by strict standards and ethics.
Over 1,200 agents listed and it helps you track your queries.
Another important place to look is at workshops and conferences. Agents attending will often give you a free pass over their slush pile. And if you're really brave you can personally pitch to them and perhaps be able to write "requested material" on your envelope.
Good Luck. Don't give up, we're all in the same boat.