If you share my conviction that customer involvement is a critical factor in delivering excellent software, you’ll engage customer representatives from the outset of your project. Success in software requirements, and hence in software development, depends on getting the voice of the customer close to the ear of the developer. To find the voice of the customer, take the following steps:
Identify the different classes of users for your product.
Identify sources of user requirements.
Select and work with individuals who represent each user class and other stakeholder groups.
Agree on who the requirements decision makers are for your project.
Customer involvement is the only way to avoid an expectation gap, ...