Show, don't tell.

In a word, prototype.  

Then get feedback.

Why?  Well, why guess what your customers want if you don't have to?  If you're designing a product, a program, an event, or a service without feedback, you're doing more work than you need to.  Start early to get input, and keep bouncing your concept off potential users as it develops. That way, you're vetting the approach you're taking every step of the way.

Nor do prototypes have to be fancy.  The simpler they are—paper and sticky notes, cardboard and tape—the less they cost you in time and money, and the less attached you are to their success.  You can also develop multiple prototypes to get a wider range of feedback.

A great example comes from the Nordstrom Innovation Lab’s “flash build” of a sunglass app. The team actually built the app, from paper prototypes to finished product, in the sunglass department of one of their stores.  If Nordstrom’s isn’t embarrassed to hold sheets of paper up to a customer and call it an app, you shouldn’t be either.