Linking theory and practice in university teacher education is a necessary condition for the development of didactic competence. With this in mind, we developed a seminar to promote competence-oriented teaching through a continuous exchange of practical expertise with current teachers. As a result, all of the participants (students and teachers) should acquire greater pedagogical knowledge as a central element of their teaching expertise. In order to examine the impact of the seminar, we measured the development of the competence-oriented didactic knowledge of 57 participating students and 6 accompanying teachers. To do so, we used a pre–post design with different control groups. The results show a significant increase in didactic knowledge. But they also show that diagnostic competences need significant further development. Hence, in the future, the seminar will be supplemented by video-based learning elements, which in particular address the difficulty of teaching competences in classrooms with a wide variety of pupils.