Disclaimer: What I have to say pertains specifically to the literary agent/client relationship. The degrees of formality are very different in different industries—and even in different segments of my industry.
We’ve had a lot of productive discussion in the comments (thank you!) regarding professionalism and formality in business relationships, and I thought it might be worthwhile to map out my own feelings on the subject.
On “first contact,” usually the query letter:
I prefer “Dear Ms. Miller-Callihan” for the first missive, even though I immediately encourage a first-name basis relationship as soon as I start corresponding with an author. When you first email me, you don’t know me or how I prefer to be addressed (okay, you do now), so it’s best to err on the side of formality here. “Dear Courtney” is a little too familiar in this context; “Hi Courtney” is MUCH too familiar.
Extrapolating a bit: I’d encourage you to address women as “Ms. [Lastname]” and men as “Mr. [Lastname].” I don’t know any woman in the working world who, at this point, would be offended by the “Ms.,” by the way, which has become widely accepted as the default honorific for adult women. My marital status is irrelevant to the work I do. So “Ms.” it is.
On staying in touch through the querying process:
Especially when you’re a writer who is querying agents and seeking representation, there are a lot of pitfalls regarding the communication. Is it okay to check in with the agent, and if so, when? How often, and under what circumstance?
If you’re querying me, I always want to hear from you, in descending order of importance, under the following circumstances:
1) if you get an offer of representation from another agent. Please let me know if this is the case, even if you haven’t heard back from me on your initial query. Agents are human, and it’s human nature to want things that other people have. This is just as true of debut novels as it was of the hottest guy/girl in your high school. If you’ve got an offer of representation from someone, use it to your advantage and follow up with the other agents you’ve queried!
2) if you've gotten word that you have serious interest or an offer from a royalty-paying publisher. This rarely comes up, but as a public service announcement I feel compelled to say it here: Please DON'T query agents and take steps to self-publish your work simultaneously. I think there are great reasons to self-publish, which I'll discuss in a separate post if you are interested, but if you're interested in a so-called "traditional publishing" book deal, self-publishing will really mess up your chances, no matter how fantastic your book is.
3) if you have a personal or professional connection that you didn't mention in your first query. Say you write romance novels and meet Nora Roberts at a writing conference, and she offers to blurb your book. I would very much like to hear about that. But don't hold back that information from your initial query (and don't stalk Nora Roberts!); this applies only if something changes in the interim.
4) if you've been to a conference or otherwise received professional feedback (say, from another agent) and have revised the manuscript accordingly, let me know that too. I don't want to tell you not to revise, but generally speaking it's probably better to leave the work alone during the query process. Work on your next manuscript in the meantime!
5) if I’ve requested a full manuscript from you, and it’s been more than a month since you’ve heard from me. I get swamped with reading sometimes. It’s a lovely problem to have. My current clients always get priority over my prospective clients; if you sign with me, you’ll be glad this is the case! But while I try very hard to keep up with all of it, everyone needs a nudge from time to time. If it’s been a month with no word on your full, go ahead and nudge me. (nicely please.)
6) if you sent your initial query six to eight weeks ago and have not heard anything from me, it's OK to send one follow-up email asking me to confirm receipt/let you know if I am still reviewing the material.
Here are some circumstances under which I do NOT recommend following up with an agent whom you're querying (in no particular order):
1) If you've tweaked the manuscript so that Chapter 2 is now Chapter 3 and Chapter 3 is now Chapter 2, and so-and-so's name has changed. It's unlikely to affect my feelings on the work. If you find that you accidentally sent the wrong attachment, or you forgot to attach it, it's OK to send it again. Mention in the email that this replaces your initial query, and that you do not need an immediate response from me.
2) if it's been less than six to eight weeks (or the ballpark time listed on the agent's website) since your initial query. I try to be quick. It doesn't always happen. If you follow up too quickly or too aggressively, I'm likely to take a quick look at the material and (unless it blows me away) send you a nice "no thanks." My interactions with people during the query process definitely weigh into my decision about whether to offer representation. The writing is paramount, but the quality of the interactions matter too.
3) if you just want to confirm receipt of the query (and it's been less than six to eight weeks with no response). I understand the anxiety of wondering whether something's gone into a black hole, but sometimes this strategy is less about the anxiety and more about trying to forge a connection/force some kind of response out of the agent. Let your work speak for itself. Caveat: If I've requested a full manuscript from you, I don't mind a bit if you want me to confirm receipt of that. Asking in the same email where you send the manuscript as an attachment is ideal.
4) calling the office. If I have not given you my direct line (which I do only if I am seriously pursuing the project/the would-be client), please don't call. In the midst of a busy work day, a cold call from a prospective client feels like a telemarketer phoning on Thanksgiving.
5) adding me to your mailing list under any circumstances. If I want to be on your mailing list for some reason, I'll let you know.
6) if you are re-sending the same query, unless I asked you to, of course. I once received the same query-- I am not making this up-- three hundred and fifty times, often three or four times per day.
7) adding me as a contact on LinkedIn. I'll accept LinkedIn invitations from anyone I know personally, anyone with whom I have worked (as colleagues) at any time, any clients of mine or of my agency's, and anyone with whom I've exchanged emails, say regarding a revision. But lately I've had a slew of LinkedIn invites from prospective clients, and I have to admit I'm a little perplexed at why this is the case. If you're looking to engage me via social media, comment on a blog post or follow me on Twitter; I'd love to talk to you. But I don't get the LinkedIn thing.
On keeping your agent happy:
1) Be polite and professional in your dealings with me, with my agency's employees, and with anyone and everyone at your publishing house.
2) Make your deadlines. If you can't keep to the schedule we've discussed, let me (and your editor, if applicable) know as soon as possible.
3) Keep me posted on what's going on-- personally as well as professionally, as needed. I've mentioned before that I love it when my clients let me know if they're going to be away or unavailable for a few days, especially if they are waiting on me for something.
4) Write fantastic books.
5) Write fantastic books.
6) Write fantastic books.