It has been suggested that though many companies realize the importance of providing after-sales services, most do not fully understand the maximum benefit from such offerings. Though several research papers document an approach for the implementation of a service operations strategy, a practical guide for the development of after-sales services is lacking in the current literature. Therefore, in this paper, we apply existing theory and use practical insights in order to propose a nine-step methodology for the development of after-sales services. The methodology links customer value from services to portfolio management theory. Two case studies describe application of the methodology. It can be used by practitioners in order to exploit the untapped potential of providing product-service offerings, with the aim to generate greater profits and a higher level of customer service.