Education aims to equip learners with knowledge about principles that can be applied across a wide range of situations but often people do not recognize structural similarity between known cases and novel problems. Several approaches for designing learning materials to foster transfer of principles have been proposed including learning a generic instantiation, comparing instantiating concrete cases, and learning multiple representations. However, these approaches have rarely been tested against each other nor have they been examined by a broad range of transfer tasks. We evaluated the transfer potential of the different approaches separately (Experiment 1) and in combination (Experiment 2) by teaching undergraduates the principles of propositional logic. Students were tested on an extensive transfer test one week after learning. The best transfer performance resulted from the simultaneous comparison of a generic instantiation with two concrete cases. We suggest this approach for designing learning materials that introduce new principles.