Evangelizing your design system efforts can and should happen even before the system is off the ground. At the onset of your project, you can set up places to document progress of the project to help garner awareness and excitement for the design system effort. One client of mine set up an internal blog to publish updates to the project, as well as a design system Yammer channel where developers and other interested parties can share ideas, address concerns, give feedback, and ask questions. Establishing a culture of communication early in the process will increase the likelihood of the design system taking root.