One of the top reasons for startup up failure is lack of product/market fit. And that's because first-time entrepreneurs often make the mistake of launching a new business based on assumptions, without testing the market first. While you may be excited about your new business idea, if you don't get enough paying customers you'll struggle to make a success of it. Yet, with the right process "even inexperienced entrepreneurs can bring amazing products to market with excited buyers," writes Jim Semick. Here, shares here his top tips for using lean market validation to determine whether you have a product/market fit.