The easiest part of product development is coming up with the idea. To be frank, lots of people come up with inventions everyday. I would speculate that literally millions of new product ideas are spawned each week. The hard part is all the stuff that follows. It takes real persistence, tremendous fortitude, and a whole lot of time and money to bring a new product to life, and not everybody knows how to do it.
Products take on a life of their own.
They get conceived, they're nurtured, they mature, and the healthy ones spawn new ideas. In their development stage, it is important that their direction be clear. What they look like and what they do is also important. The developer needs to get quality feedback to ensure good product acceptance and development. As a result, make a plan and stick to it.