This paper presents, illustrates and discusses theories and practices about the application of a domain-specific modeling (DSM) approach to facilitate the specification of Visual Instructional Design Languages (VIDLs) and the development of dedicated graphical editors. Although this approach still requires software engineering skills, it tackles the need of building VIDLs allowing both visual models for human-interpretation purposes (explicit designs, communication, thinking, etc.) and machine-readable notations for deployment or other instructional design activities. This article proposes a theoretical application and a categorization, based on a domain-oriented separation of concerns of instructional design. It also presents some practical illustrations from experiments of specific DSM tooling. Key lessons learned as well as observed obstacles and challenges to deal with are discussed in order to further develop such an approach.