If you wrote a book about wizards when Harry Potter came out, a vampire story when Twilight became a movie and a dystopian action drama most recently, you're not a slave to inspiration...you're being way too trendy. Authors are terminally uncool...so it's really just best not to try to keep up with the tide of public favor.
I'm a Barbie Girl
Everyone loves a fad, and I'm no exception. I turn certain movies into full-blown events. I consider myself to be pretty fashionable and trendy...but I don't try to follow book trends. For one thing, they come and go too quickly. By the time I started considering writing a book about wizardry, Twilight was already the next big thing. And before I even had the chance to consider writing a vampire book, it was all about The Hunger Games.
But even that isn't a good enough reason not to follow trends. You only really need one: you should be writing what you want to write. If you've ever started a novel, grown bored and started four more different novels, you know what I mean. When you have a story that's just aching to be told, you can hardly stop writing -- or thinking about it. If you're only writing something because it's trendy, you aren't writing at your best...or with your whole heart.
So ignore the trends in books, and stick to the trends in fashion (like me). This will help you design more attractive book covers, which is really the only literary trend you ought to bother following at all.