With that being said... in general, I think most people find it helpful if their recipient gives them *something* to work with in the request email, in terms of specifics. After all, if you just wanted to write a random story in an obscure fandom, there's nothing stopping you from doing that the other 11 months of the year. Yuletide is about writing a story because you know that there's someone out there who *wants* that story, and so it helps a little to know what that person actually wants.
Here are some guidelines I think might be useful in terms of making Yuletide requests.
1) Do give your writer something to work with.
2) ... But don't go too far with it.
3) Give your writer an angle to latch onto.
The first guideline is easy. Just give your writer something to work with. If you really would be happy with absolutely anything at all, about any character on the list, then that's great! And telling your author that will probably help to encourage her. However, even if that's the case, surely there's one or two things that would make you *even happier*, or one or two things you could steer them away from.
For my examples I will be using the imaginary fandom "Ghost Soup." :)
For example, here's what you might write if you really, honestly would be happy with *anything* and didn't want to overburden your writer with specifics. (This is supposing you picked "Any" for your requested fandom, rather than specific characters.)
Not very helpful: "Anything would be great. Thanks!"
More helpful: "Anything would be great! I'm totally okay with gen, slash, het or femslash, I'm open to any pairings between the characters that I listed, and I don't mind death stories." (Of course, if you DO mind death stories or would prefer gen/het/slash in this particular fandom, this would be the time to say so as well.)
Even more helpful: "Anything would be great! If you want a prompt, though, it would be awesome if you could write something during the period where they were all lost in space, or something focusing on Moira's backstory, or Angela's relationship with her clone, or maybe a story about the Josh/Ryan relationship (either friendship or romance). These are just some suggestions, though; if none of those appeal to you, then just write anything in the Ghost Soup universe and I'll be thrilled." (Insert bit here about how you're okay with any genres and pairings, really.)
This is really especially important if you're requesting a story in a fandom with a huge scope, like a book series or a long-running TV series, or any source that is sufficiently epic. I mean, to use a different example, if you were requesting a story in Harry Potter, it would be fine to say "Anything's good with me!" -- but there's so much *there*, it could be a little paralyzing for your author when it comes time for her to decide what to actually write about. The Trio? The Marauders? The Death Eaters? Post-series-fic? Pre-series-fic? The teachers at Hogwarts? Etc. Even if you really, really have no preference, it would ease your writer's mind if you said explicitly, "I would be thrilled with any story-- anything about the Malfoys, the Weasleys, the Potters, the Hogwarts teachers, I'd just love a good HP story."
However, there is such a thing as going too far with it. How far is too far? Pretty much anything that specifically outlines the story.
Bad: "I would like a Ghost Soup story where Luke makes out with Angela's clone and Angela gets mad and seduces Moira just to make Luke mad, and then Ryan and Luke duel to the death with their lightsabers and it ends up in an Angela/Angela's clone/Moira threesome. And Ryan feels really bad and flies off to Mars forever."
Everybody understands what it's like to really, really want one particular story in a fandom, but the thing is, if you really, really want that specific story and no other story will do... Yuletide is not how you're going to get it. (And it's not how you should *try* to get it.)
Suppose you really do want a story *like* that, though. What's a good way to ask for it?
Better: "I love femslash, especially any combination of Angela, Angela's clone & Moira, but I'm also okay with Luke/Angela or any of the canon Ghost Soup pairings. (I'm also okay with threesomes.) I also really love Angela angst and Ryan angst, and I love stories that include jealousy and pining. Also, a lightsaber duel would be awesome, and I'm okay with death stories."
You probably won't get the exact story you were imagining-- which is fine, because again, that's not really how Yuletide works-- but you've given your writer some indication of how to make you happy, and you might be surprised with what they come up with. You should always give your writer room to surprise you; Yuletide produces some amazing stuff every year, and one of those amazing stories could turn out to be for you. :D
The third guideline is, again, more helpful if you don't really have a specific story in mind. Again, going back to the Harry Potter analogy. It's one thing to say "Yes, write me anything!" But there's so many possibilities in HP that your author might freeze up. Or she might play it safe, since after all she doesn't know you or your particular squicks. (Sure, you said *anything*, but does that really mean you'd be okay with Fleur/Hagrid/Giant Squid deathfic?) This is the part where writing a letter to your writer and posting it in your journal might help.
Give your writer an angle to work with. What does that mean? Basically, instead of naming specific characters or plot points, you talk about why you like the particular fandom you chose for Yuletide. It's easy to think "Well, it's obvious. Everyone likes Ghost Soup for the same reasons I do." But even thinking about a popular fandom like HP, people like it for all kinds of different reasons. Maybe they like reading sad ominous stories about the Marauders and their doomed loves. Maybe they like exploring the details of the wizard world, the spells and laws and infrastructure and wordplay. Maybe they like hilarious boarding-school hijinks and adorable first love. Maybe they like gruesome Death Eater ritual orgies. Maybe they have a teacher/student kink. Maybe they like all the different possibilities for pairings that you can only get in HP, like ghost/human or vampire/veela, and so on and so forth.
So, talk a little about why your fandom appeals to you, or why you like the particular characters, and it will help give your writer something to work with in terms of understanding your perspective and what kind of story you might like. (For examples of what this looks like in practice, you can check out some of my previous letters under the tag yuletide on my journal.)
The other benefit of writing a letter like this is that it can also work as an effective way of pimping your rare fandom. :D Tell everyone why it's so awesome! Post pictures! Include quotes! I usually don't pick fandoms that are *obscure* so much as they're *underwritten*, but I'm always interested in reading about other people's rare obsessions. :D
Finally, one last thing that might be helpful when it comes to actually *requesting* fandoms-- if you feel comfortable with doing so, think about including a "gimme." By a gimme, I basically mean, a fandom where it would be very easy for your writer to get hold of the canon and familiarize herself with it in a short amount of time.
Think of it this way. Suppose you get your request in the mail, and it looks like this:
1) Mystery Series With Eight Books In It
2) Big Huge Fantasy Trilogy Followed By Another Trilogy
3) Manga That's Up To Book Ninety-Three Already
4) Comic Book Series That's Been Going On Since 1963
Now, suppose you got a writer that signed up to write #4, and that's the only one that they're familiar with. But unfortunately, for *whatever reason*, they get stuck. Maybe it's just a total mental block or a mismatch of expectations, but they just don't think they can *do* this fandom this year. Maybe they could write something in one of the other fandoms-- except they really don't think they can get through eight mysteries or six fantasy novels or ninety-three graphic novels during the holiday season... They're stuck.
Alternately, your writer could have to drop out for some unknown reason-- with as many people sign up each year, it's near-inevitable that a certain percentage will have family emergencies, illnesses, or just flake out. Think about the pinch-hitter who might get your request a month before deadline, or even closer to the very last minute, and who feels like she has to re-familiarize herself with the canon details before she even starts writing.
Personally, I always try to include a movie fandom in my requests, just in case someone runs into a pinch like that and is like, "I can't write this! Maybe I should familiarize myself with another one of these fandoms on this list..." A relatively non-obscure movie that can be easily bought or rented is a good "gimme" fandom. Alternately, perhaps a short novel, easy to get through-- something more like "Bridget Jones" than "The Count of Monte Cristo." But a movie is probably best.
Now, if your top four choices for Yuletide fandoms are all epic or lengthy, and if some random "movie fandom" is a far second best to any of your first choices-- then I really would not advise you to take one out and add a "gimme" fandom. You don't want to be disappointed by getting a Yuletide story in a fandom you only included as a gimme. So really, don't do it if you wouldn't love a story in *that* fandom as much as all the others!
(The other thing you *could* do might be to "consolidate" your fandoms a little. Instead of requesting "Mystery, Fantasy, Manga and Comic," think about requesting 2 manga series and 2 mysteries, or 2 fantasy series and 2 comics series. Just from my own personal experience, I know that if I request "Flash (comics), Starman (comics), Hellboy (movie) and Superman Returns," I can generally be pretty sure that if someone's familiar with one, they may well be familiar with one or two of the others as well... However, I usually wouldn't go so far as to pick 3 DC-comics-related titles. This is a theory I'm still kind of working on, though.)
Personally, I usually don't have a problem coming up with movie fandoms to request; I don't really read/write bookfic, so for me it's easy. I'm perfectly content to request, for instance, Obscure Comics Series, Obscure Comics Series, Movie Fandom and Movie Fandom. But if you're in a situation where you're trying to narrow down your list of fandoms to four, and you've got a handful of fandoms that you just absolutely can't decide between-- then this might be a factor you'd want to consider. "How easy would it be for a writer to familiarize (or re-familiarize) herself with a fandom on my list?"
Anyway. Like I said, Yuletide is so massive and so all-encompassing these days that it's hard to say even "in general" what is a good strategy or what most participants do or prefer. With that in mind, I'd love to hear comments or stories from people about what kind of prompts or requests were helpful to them, and (if possible, without bashing) perhaps some constructive criticism about what kinds of things could have been more helpful in the past. Does anyone else have any ideas about Yuletide requests? Please leave a comment.
Other Posts of Interest:
-- shusu has a really neat post here for Yuletide newbies-- not just addressed to writers, but to everyone. Really good stuff.
-- thefourthvine actually went about this scientifically and did a poll a while back; this post summarizes some of the things she's learned from her Yuletide experiences & from that poll. Very well organized & a great resource.