A persona, in user-centered design and marketing is a fictional character created to represent a user type that might use a site, brand, or product in a similar way.—Wikipedia

You need to get a better understanding of who your users are and how they may respond, reflect or react to your product / application. To do this, its best practice to create personas. For my last project I created 5 separate personas, trying to capture 80% of the carriers that the client dealt with on a daily basis.