1. Identify basic requirements Determine basic requirements including the input and output information desired. 2. Develop Initial Prototype The initial prototype is developed that includes only user interfaces. 3. Review The customers, including end-users, examine the prototype and provide feedback on additions or changes. 4. Revise and Enhance the Prototype Using the feedback both the specifications and the prototype can be improved. Negotiation about what is within the scope of the contract/product may be necessary.