This article presents the use of a model-centric approach to facilitate software development projects conforming to the three-tier architecture in undergraduate software engineering courses. Many instructors intend that such projects create software applications for use by real-world customers. While it is important that the first version of these applications satisfy the customer by providing the functionality the customer expects and perform reliably and efficiently, it is equally important to be able to accommodate the customer's change requests over the period of the product's lifetime. The challenges in achieving these goals include the lack of real-world software development experience among the student developers and the fact that post-deployment change requests will almost certainly have to be handled by students who are not among the original developers. In this article, we describe how a model-centric approach using UML has been effective in enabling students to develop and maintain eight software applications for small businesses over a 9-year period. We discuss the characteristics of our modeling technique, which include the application of modeling patterns and quality check rules that enable students to create a model that can be clearly and consistently mapped to code. We also describe the nature of these mapping-to-code techniques, emphasizing how they reduce coupling among the implementation's classes. We then discuss our experiences in the classroom with these techniques, focusing on how we have improved our teaching over the years based on the analysis of student performance and feedback. Finally, we compare our approach to related work teaching modeling and the development and maintenance of code in software engineering courses with both extensive and minimal modeling.