I try to emphasize as much as possible the use of first principles in physics. Science, including physics, is based on a small number of principles, relationships between concepts, that can be used to explain and predict a vast number of phenomena. I also emphasize computational approaches while doing physics and solving problems.
In my introductory physics classes I use mainly active learning laboratories (Real Time Physics labs), tutorials (University of Washington Physics Tutorials), and collaborative group work. Students work in groups during class, evaluate their team members periodically and are also evaluated (Team-Maker and Comprehensive Assessment for Team-Member Effectiveness (CATME)). This gives them feedback which helps in acquiring group work skills. Active learning lab exercises are typically used when a new concept or principle is introduced. The laboratories can address each student's individual preconceptions, while at the same time, providing experience of how physicists (and other natural scientists) work in practice. Tutorial exercises are used to solidify the concepts and principles and increase conceptual understanding. During class, my students typically work in groups doing labs or solving problems on the group's whiteboard. In upper level courses I use mainly the Just-in-time-teaching and collaborative group work techniques. Students have a reading assignment before class, and I use the Just-in-time-teaching approach to probe their conceptual understanding and decide how to spend class time. During class, my students typically work in groups, mainly solving problems on whiteboards. During the semester students evaluate their team members periodically, and are also evaluated.
In my introductory physics courses I use the innovative Matter & Interactions curriculum, which is based on fundamental physics principles and uses computational techniques to do physics.
Another characteristic of my approach is the use of materials developed by research on physics education, and materials proven to be effective for student's learning. For example, I use the Intermediate Mechanics Tutorials developed by Bradley S. Ambrose and Michael C. Wittmann in my upper level mechanics courses. In most (if not all) courses, students have to work with computational models of physical situations that helps them understand concepts and principles better as well as appreciate the contribution of computational sciences in the advancement of science.
Assessment is used in all classes, in order to assess student-learning and introduce changes in future courses.