This work is an investigation into the optimization areas in after-sales service for small and medium-sized enterprises (SMEs) in plant engineering, as well as the resulting recommendations for action for the further development of strategic and operational business processes in customer relationship management (CRM). The practice-oriented study explains how extensive and complex the development and optimization of services can be, which customer relationship management tools can assist in this process, and how an optimization strategy can be implemented in small and medium-sized enterprises. To identify the optimization areas, a case study on customer satisfaction in after-sales service is conducted, the findings of which ultimately contribute to practical recommendations for service optimization.