Shared Product Vision
Ensure that you have a shared vision in place that describes the target customers and users, the needs the product is going to address and what the product will roughly look like and do. Consider not only the key functional attributes but also non-functional ones including user experience and operational qualities such as performance and robustness. Use prototypes and mock-ups to develop the vision and to gather feedback from target customers and users.
Envision the minimal marketable product – a product with minimum functionality that meets the selected customer needs. This shortens time-to-market and allows you to find out quickly how the market responds. If the response is not great then adapt then product to better meet the customer needs. Note that even if you carefully select the target customers and users to gather early feedback as described below, their views might not be representative for the entire market or market segment. And hardly ever is the first version of a product perfect.
Early and Frequent Customer Feedback
Third, gather early customer and user feedback by inviting (selected) customers and users to sprint review meetings and by releasing product increments early and frequently. This integrates customers and users into the development process, and it lets the product evolve based on their feedback. It also shows you quickly if you are shooting for the right goal or if your product vision is ill-conceived.