Authors who are interested in submitting to a traditional publisher often ask about the best route. I recommend that authors query agents first. Whenever you approach a publisher yourself, you are closing the door for an agent to submit on your behalf with that publisher. So spend some time looking for an agent before you submit to publishers.
The question then becomes, how many agents should I query before shifting to publishers? Generally I recommend no less than 50. It is actually more difficult to get an agent than a publisher these days. Because they can do so much for an author, though, it is worth the effort.
Authors who have been picked up by traditional houses often recommend 80 queries! This is because an agent’s opinion can be as subjective as that of an acquisitions editor. So don’t give up after a dozen or so. If finding that number of agents sounds too tiresome, consider an agent list tailored to your needs. Writer’s Resource offers lists generated anew for each person (and even each book) that average 60 to 80 agent names. Some lists produce over 100 names for authors working in popular categories. Visit the website and look at the Agent tab for more info.