This chapter discusses aspects of the product development process, including ways you can incorporate human interface design into that process. First, this chapter presents several issues to consider when deciding on the features you want to include in your product. Second, this chapter provides suggestions for how to make your product simple and easy to use; too often, users are confused by unnecessary complexity in an application. Next, this chapter describes how to extend the interface when your application requires functionality that isn't covered by existing user interface elements. Finally, this chapter discusses the benefits of involving users throughout the entire phase of your product development process.