This paper describes design strategies that led to significant improvements in the usability and learnability of an end-user programming environment called RIDES. These strategies may be viewed as concrete procedures for building easily learned interfaces and were derived from Polson and Lewis' CE+ theory. RIDES was designed to make it possible for US Air Force training experts, with minimal programming experience, to author simulation-based Intelligent Tutoring Systems. Using the techniques described in this paper, the researcher reduced, by 1/3, the time it took to learn and use the redesigned RIDES system. (2001-01-01)