Whether you are developing a disruptively innovative product or a uniquely repurposed solution, and no matter how clear your idea and vision seem on paper, designing as simple as a paper prototype is ...

Opinions expressed by Entrepreneur contributors are their own. Amazon Fire Phone, Google Glass, New Coke and Nintendo’s Virtual Boy: What do all these products have in common? They didn’t sell.

When your product is being ripped out of your hands by eager customers and you cannot keep up with their demand for more, you have achieved the nirvana known as “product-market fit.” Most startups ...