Extensive field tests of four new introductory physics courses, in which the new models were compared with more traditional courses, have yielded many results. The most interesting of these are not directly related to how the new models fared, but instead to general features shared in common by many physics courses. The theme is simply that it is important to set concrete and well-defined goals, and to design every in- and out-of-class activity so that the students’ time is devoted to achieving those goals.