A reference architecture is a complex and high-risk artifact. It is essential to the successful definition and management of a set of architectures that share common attributes and assets. You simply cannot afford to get it wrong, but there are few techniques that have been specifically aimed at defining reference architectures. We have developed a mashup of existing techniques that supports an architecture team in organizing the inputs required to create a robust reference architecture. This mashup takes advantage of several proven, widely used architecture methods. This approach allows the architecture-definition team to incrementally define the appropriate abstractions and patterns and to organize the information so that it is accessible and actionable. The resulting technique has been applied to a large development effort aimed at creating a family of embedded computing architectures and applications for the DoD. The mashup is proving to be effective at focusing the team and giving them practical and proven tools for coordinating their work and making meaningful progress.