There is no one hard-and-fast rule or formula for what makes a given product “right” for your market and your customers. It depends on your field and your customer.
This is something you need to make the effort to develop a sensitivity to. To some degree, it is more of an art than a science. (Though there are clearly things not to do. Commercial history is littered with examples.)
For the scientist, it has to do with rigorous research, repeatable experimentation, detailed descriptions and conclusions, and peer review. For the shaman or priest, what makes their products salable may be relevance to people’s lives. You must figure out what constitutes right for your particular product, service, business, or whatever extended retail activity you are engaged in.
Potential customers for every type of retail activity in the 21st century are extremely sophisticated. They can sniff out whether or not the product is authentic and right for them. Even in the last century, the Edsel, despite all the extensive and expensive design and the most sophisticated market research of the time, was not authentic—and people just didn’t want it. All the elaborate presentation, distribution, and advertising could not make it a winner. UGG boots, in contrast, are clear and continuing winners— in part because they are authentic and deliver value, along with the other qualities that make the product right.
This is a short excerpt from my book, due to be released June 2019.