The importance of model composition in model-centric software development is recognized by researchers and practitioners. However, the lack of empirical evidence about the impact of model composition techniques on developers’ effort is a key impairment for their adoption in real-world design settings. Software engineers are left without any guidance on how to properly use certain model techniques in a way that effectively reduces their development effort. This work aims to address this problem by: (1) providing empirical evidence on model composition effort through a family of experimental studies; (2) defining quantitative indicators to objectively assess key attributes of model composition effort; (3) deriving a method to support the systematic application of composition techniques; and (4) conceiving a new model composition technique to overcome the problems identified throughout the experimental evaluations.