The more I look around this business, agents are looking for what's selling, and if you don't happen to have the idea of the month, you're out. For instance, I'm sure Stefenie Meyer's book was part perfect timing for vampires.
No, Stephanie Meyer's book created the desire for vampires. Good books always do this. If your book sells only because it's the idea of the month, you're probably late, and someone else already write something original and hot that made the idea of the month what it is.
No one, not agents or editors, brainstorms for idea of the month. They just want really good boos. Period. If the book is good enough, it
creates the demand for more books similar books in that genre.
Yes, agents are looking for what will sell, but what sells best is never a book that copies the idea of the month, it a new and somehow original book with a story readers want to live, and with characters readers want to spend time with.
This is what agents and editors are always looking for, and genre, or the idea of the month, play no part in it. Whether it's Carrie, or The Hunt for Red October, or Twilight, or Harry Potter, the book creates the market, creates the desire, because it's good, new, and somehow original.
Not too many years ago, the western genre was as dead as a genre can get. No on wanted westerns of any kind, for any reason. Then Larry McMurtry wrote Lonesome Dove. Not only did it win The Pulitzer, it brought the western market back to life almost overnight.
I've seen this happen time and time again. Good agents and editors don't read manuscripts to find the idea of the month, they read to find a book with story and characters they
love, whatever it's about, whatever genre it's in. If they love it, the rightfully assume a lot of readers will love it, as well.
The idea is to write just such a novel. If it's good, if it's somehow original, and if it has a story and characters agents an editors love, the book will sell, and any "idea of the month" that comes after is just coming in late. You need to write a novel that creates the "idea of the month", if there even is such a thing, which I doubt.