Whenever we ask people, "What should you do if you have a great idea?" the answer is always the same: write a business plan, raise some money, hire a team, build the product, and, when the product is finished, go out and sell it. This answer isn't a surprise. In fact, it represents our collective wisdom about how to develop a product. Yet following this model will almost always reduce your chances for success.
(See Nail It Then Scale It, pgs. 8-13)