In this deck I describe twenty best practices for using external DSLs to develop software (also know as Model-Driven Development). The best practices are based on my personal experience, but they are also rated based on feedback I received from a number of colleagues to express the level of confidence experts have in the particular best practice.
The slides cover three main aspects: language definition, model processing as well as process and organizational issues. Examples include the importance of notations, viewpoints and partitioning, the role of constraints, model transformations and testing as well as some thoughts on documentation, reviews and project roles.
Putting twenty best practices into 5.000 words of course results in each best practice being quite brief. However, it also means each is highly condensed and to the point. I believe the slides remind developers of most of the critical aspects of using DSLs, and it can serve as a checklist when starting an MD* project.