Tweet-Q: Would you rather rep a writer with a deal on the table? I heard this is ideal for 1st.I don't presume to speak for every agent here, but for myself, I'd actually say this is a less-than-ideal situation.
If you have an offer from a publisher already, and you query me (or any agent) with a subject line like "Offer From Random House!" or similar, I will definitely read your query immediately. However, that is by no means a guarantee that I'll offer rep.
I still have to love the book.
Also, when I send out a project that is MY project, I have worked hard to craft a great pitch. I've made sure that the manuscript is in as good a shape as I can make it. I have created a submission list based on both my knowledge of individual editors tastes and needs, and with the input and advice from my entire agency. Publisher expectations are also set - they know the kinds of rights I am going to want to keep, for example, and they will make their offer accordingly. I have often timed the submission in a particular way for a particular reason... and I find that I have a pretty good success rate.
When YOU do those things, and then try to bring me in after the fact, I haven't been able to do any of that good stuff, including (especially) choosing the editors that I think will be the best fit.
The offer on the table is usually not a great offer. The publisher is usually not in a particular mood to negotiate considering that there was no agent involved when they first made it... so while I'll probably be able to negotiate the advance up to cover my commission, and improve the terms, it isn't like you'll be leaping into a totally different sparkly-deal stratosphere just because you hired me.
The point I'm making is, it is fine to do things backwards and get an agent after you get a deal, it will probably help you and certainly won't hurt you. But it is by no means better to do so. And I personally think you are likely to get a better deal with an agent in your corner from the beginning.
(And for those who think that they CAN'T get an agent as a debut author... I'm gonna have to call shenanigans on that one. Half my clients are/were debut authors!)