Giving successful instructions, especially when they are formulated in a second or foreign language, poses a number of important challenges for novice teachers. This paper traces a student teacher’s development in giving task instructions over the course of a CA-informed university module. The data include the microanalytical description of instruction-giving sequences at two different points in time during the school-based practicum and other ethnographic data such as feedback from the supervisor and the student teacher’s reflections both in the final practicum report and in an interview with the researcher. The results show that the student teacher’s instruction-giving sequences improved over time, and that this development was accompanied by her increasing awareness of the importance of task instructions and the factors contributing to their success. Furthermore, the results indicate that all components of the CA-based module, including the course readings, the feedback received, and the task of transcribing her own teaching sequences, contributed in different but equally important ways to both her teaching performance and her awareness of the features of classroom interaction.