I'm often asked by "new" writers when it's a good time to send out your material without an agent: my answer, which takes into account a writer's best interests, is that I can think of very few circumstances when you shouldn't try to submit to publishers through an agent.
Many writers are tempted to forgo an agent, often hoping to keep that extra 15% for themselves. Other writers submit their unagented material to publishers-then, before they hear back, follow up their submissions with queries to agents, essentially working at it backward.
Allow me to illustrate just a few of the many things that can go wrong when you submit unsolicited, unagented material to a publisher-even if you intend to seek an agent later on.
Your material will not seriously be considered. In some cases, it may not even be opened. I've talked to editors who've said, "she's a great writer...but we didn't take her on because she didn't have an agent."
You demonstrate, intentionally or not, a professional disadvantage — after all, you'll be competing with writers who do have agents—friendly, professional faces to put with their manuscripts, and not yours.
You forgo the advantage of an agent's critique. An agent's feedback can give your writing the extra edge that will mean the difference between publication and not.
If you submit your writing to a category publisher first, then seek an agent as a second thought, you've put your potential agent in a bad situation. If you're writing category, your book can probably only go to one house, one imprint. If you've already sent your book to that one single house that it's appropriate for, what exactly do you expect of an agent if you don't already have a contract? Better to wait for the contract, at that point, then take your pick of your favorite agent to negotiate it.
You might tie your agent's hands, so to speak, if you submit to publishers before querying her. If you submit your book to a publisher, then snag an agent, then quickly hear that said publisher wants your book, it means you've probably eliminated any chance of your book going to auction and getting a bigger advance. Unless your agent was able get your book out to a handful of publishers before the offer came in, she won't be able to leverage that offer to get you a more advantageous deal at a more competitive publishing house.
One last hint: When you're at a writer's conference, you may want to make appointments with agents over editors. Why? Other than the advantage of getting an agent on board before pitching to an editor, if you pitch to an agent, and she agrees to represent you, you've essentially just pitched your book to dozens of editors because your agent has connections that you probably don't. If you pitch to an editor, you pitch to an editor. Make more efficient use of your time by pitching to agents first.
