There is the eternal question of trying to write a book that cashes in on a hot trend. Authors say, “I’m going to write a thinly veiled novel about being a tyrannical CEO’s assistant (or movie star’s assistant, or editor’s assitant, or a blogger from Terre Haute’s assistant, whatever) and hit the bestseller list.” Or, they’ll try to cash in on some political event or discussion. “Global warming is really a hot topic right now,” they say.
It sounds like a great idea, but agents and publishers are looking for books so far out in the future that the hot trend today may be completely forgotten by the time your book is published. For example, the lovely Miss Snark is buying books for 2009 right now.
So the simple answer is to just write well, without regard to trends. And leave the hot topics for the mall.