A multi-stage study of the practices of expert courseware designers was conducted with the final goal of identifying methods for assisting non-experts with the design of effective instructional systems. A total of 25 expert designers were involved in all stages of the inquiry. A model of the expert courseware design process was created, tested, and refined through four try-outs. The final version of the model included instructional design task descriptions and electronic worksheets. The study revealed a common expert process that included the use of rapid prototypes, an opportunistic method of applying 14 key instructional design tasks, 8 success factors related to courseware design, and design guidelines for 10 preferred instructional strategies for courseware. (Contains 6 figures and 6 tables.)