Sorry, but no trends, no matter how awesome, last forever.
We--the agents, frugal bunch that we are--found a bar that offers $3 margaritas (blended or over ice) and mojitos (mmm, minty). In a city where $14 + tip is not unusual for blended/muddled/fancy drinks, this is an excellent deal. So. Picture, if you will, five young agents around a round table. Three in the booth, two in chairs. The walls are painted white with vintage ads; a giant Coca Cola sign--it must be five feet tall and eight feet wide, at least, of steel and red neon lights--stretches over the wall behind the bar.
And the subject, in this vintage-inspired setting? Bringing YA up to the real present--out of the vampire/werewolf/angel/demon-infested, paranormal worlds--and getting a fair advance. Contemporary YA. "Contemps."
See, we think this is the direction Young Adult is going. Are editors tired of magical creatures? Yes, a little. Will such creatures continue to sell for many years? Probably, though I don't think this subgenre will dominate the market in the same way it has the past few years.
The problem is that the sales departments--and this is often true; sales departments are (according to some, simply behind; according to others--don't hit me; I like the Midwest--"Midwesterners, not New Yorkers, so they aren't up on these things") not usually on the same page as edit-staffers. Their motives are slightly different: sales teams want books that are safe, proven investments that will make lots of money; edit-staffers want amazing books that happen to make lots of money. Do they care how a book does? Yes, of course; sometimes editors are fired if they consistently buy books that lose money. But they care more about each work's content. And they know when an as-yet-unproven subgenre will do really well.
This wave of contemporary YA hasn't been proven to sales departments yet. Demons have.
So. What does this mean for you?
If you're writing paranormal, unless the economy magically picks up, you know, right now, you're probably going to have your best shot at getting representation and a good advance now. Does this mean you should send out something that isn't ready? No. Good sense always trumps trends.
If you're writing "contemps"--contemporary YA works that are in the "real" world (though, of course, teens' worlds often blur the line between what is real and what feels real), well, congrats! You are, I believe, writing the new big thing. Editors will love that you're new and fresh. Agents will know the editors that are looking for your work. But your advance will not have a very good chance of being, you know, ginormous just yet.
Does this mean you should wait? No. Yes, GK will probably update you on this trend, perhaps with line graphs, and perhaps send out a furious, YES! Right now! Send your contemporary YA out RIGHT NOW! post from her mobile phone. But you always want to err on the side of being at the beginning of a trend, if possible. And it's likely that, by the time your book comes out, the trend will be in full swing.
And you must always remember that, the moment you earn out your advance (that is, the moment the publishing company breaks even after paying you that sum), you become a good investment. The sales team will like you even if you don't have any demons. And you can still make just as much; it's just that it'll come as royalties, not advance.
It's like surfing (and Swordfish Shirt Guy could back me up on this): timing is everything. It's always better to be too early--you (your book) are in the path of the wave, which will come up and meet you (probably by publication). You'll have plenty of time to gauge where that is and adjust accordingly. Slightly too late, and the wave will crash on you, you'll get pushed underwater and rolled to shore, with decidedly uncool seaweed and sand in your hair. And, if you miss the wave entirely, you'll have to wait for the next one, which may be awhile--but at least you (and your sales record) didn't get pummeled.
One of my favorite things about ocean, wave-based sports is that you can really feel what's happening in the water, even if (like me) you can't see very well without, you know, glasses or contacts or corrective lenses that do not agree with salt water. You can feel a wave coming. You can feel the water pull back from the shore, and the force with which you can be sucked into a wave about to crash.
So picture us, five young agents with mojitos, margaritas, and surfboards. Even if it's suddenly sweater weather in NYC, we're in the water and feeling a contemporary wave coming. It's just a gentle tug of the water now. But it's enough that we've all noticed it, and are planning accordingly.