As an aspiring author, it's important to keep a keen eye on the "NEW" bookshelves in both bookstores and libraries. By keeping your reading list current, you're keeping your finger on the pulse of the market. Just as in fashion, there are trends in the book world. If you're writing a book you intend to sell, especially if it's one you've had on your desk for a while, you need to make sure that manuscript would be marketable in today's world.
Don't delude yourself. Reading someone else's work, even if it's similar to yours, WILL NOT pollute your writing. It will enrich it. Don't get me wrong---you should never copy or plagarize in any way. But you should read the kind of books you write. Note the elements that pop up in every title. And then note the new trends---new styles, new types of characters, etc.
Take the romance genre for example. Gothic tales filled with brooding heros, dark dungeons, and isolated castles were all the rage in the 60's and 70's. The eighties were all about sucessful business men, the boom of the comtemporary romance, and money. Lots and lots of money. We we all watching Dallas while we read Jackie Collins. And remember all those great Judith McNaught novels? And who can forget Jayne Ann Krentz's eighties books? The last few years have been all about the paranormal. And paranormal likely wouldn't have sold in the days of Boy George and WHAM!. And even if it did, it would have been to a smaller audience. Who knows what the newest trend will be?
Ever notice how lots of best-selling authors start writing different kinds of books, even after major successes? Sandra Brown now writes romantic suspense---not short categories. Brenda Joyce is concentrating on paranormals instead of historicals. Even established authors have to follow trends sometimes.
Sometimes, writing for pleasure is a different game that writing for commercial success. Sure, you should write books you would like to read. But don't kid yourself either. Be honest with yourself when you reflect on WHY you write. And if you're writing to become the next top-seller, you need to know the market inside and out. I'm not suggesting that you "write for the trend" because you may be too late to catch it. What I am suggesting is that you read widely and figure out the baseline of your genre. Once you know that, you can easily spot what's new and hot and marketable.
Writing a manuscript fitting the expectations of today's reader goes a long way in getting it published.
In short, nobody wants to buy a Hummer right now. We're all thinking about Hybrids and MiniCoopers. Make sure your book is not a Hummer. Who knows when they'll be back en vogue?