Why ARE you a writer? If it's for one of the following reasons, you're in the wrong business.
1. "One bestseller, along with a movie deal, will make me so rich I'll never have to work again."
2. "I'll be famous and people will adore me!"
3. "Writing a book is easy. All I have to do once I get published is travel the world, on my publisher's dime, and sign books."
4. "I need an extra income and this is the easiest way to do it."
I'm going to explain why each of the above could be the kiss of death.
1. One bestseller likely means years and years of non-bestsellers, novels that don't sell, and query letters that go nowhere. Most authors are in the business for a long time before NYT even notices them. Take Debbie Macomber or Nora Roberts. Both wrote category romance for a decade or more before a single title went to the top of the NYT Bestseller list. Sure, they're perennials now, but that wasn't always the case. And unfortunately, a movie deal is not included in the sale of a book. It's a la carte and depending on what you write, it may never happen. Publishers depend on bestselling authors to keep writing. One book won't cut it.
2. Okay, so people may adore you, but not because you're instantly recognizable like Paris Hilton or Michelle Obama. Yes, once you're published, people will look at your dust jacket and see your photo. But few authors look like their "book photo." Also consider that movies are visual. So are politics. Writing is still two-dimensional. When is the last time you saw an author playing the heroine in a movie based on her book? Consider this---A friend of mine, an NYT Bestselling author of suspense novels, sells a book in the US every six seconds. (He's in about a billion other countries, too.) According to him, he's been recognized exactly twice outside a signing or a conference or other place where people were expecting him. One of those occasions was on a flight to Australia. His neighbor was reading one of his hardbacks with the huge photo. After a few hours, he recognized the author. You know this author's name; you think you would recognize him. But you likely wouldn't.
3. Writing a book---any book---IS NOT EASY. Every step is a challenge. Most people who successfully transition from writer to author do it in years---not in days or weeks or months. Yes, I know, there are books and DVDs that promise you can write a book in thirty days. Maybe you can. But can you polish it, revise it, AND sell it in thirty days? Not likely. Unless you're a celebrity or a wronged political wife---that package comes with a ghostwriter. As for traveling the world, most authors have a tight marketing budget. Unless you're Nora Roberts or Dean Koontz, your publisher will not pay for frequent trip to Monaco or Bali. You'll be stuck in your office, typing away, trying to meet your next deadline. Books make money for publishers. An author sucking down Sangria in Barcelona does not. You have to make time to actually write books if you want to keep your publisher. And your agent.
4. If you need extra income, writing isn't necessarily the best way to get it. If you have experience you can possibly get work with a local newspaper or an online magazine, but becoming a novelist when you've been a banker or a nurse requires you learn a host of new skills. The learning curve is steep and the skills needed to write and sell a novel take years to acquire. It takes four or more years to get a Bachelors. It will likely take at least that long to make a splash in publishing. Don't kid yourself---if you're in dire straits financially, do something more concrete. Avon or eBay. Don't put yourself into a deeper bind by thinking this is something you can accomplish in a weekend.