Teacher research provides a tool for developing, encouraging and sustaining teachers' and student-teachers' reflective practice. The process of carrying out such research leads teachers to analyze their practices, their teaching decisions, and their personal style, which is difficult to achieve with other types of professional activities. This paper discusses a strategy employed in the obligatory teaching practice component of a Teacher Education course lasting one year, which involves two types of teaching activities; inside the Institution and in the school classrooms. Student-teachers are organized into groups and an advisor observes the members of each group throughout the year's teaching practice activities (TPA). Most of these activities are videotaped as they are used for reflection and discussion in the groups formed by the student-teachers and their advisor. After each activity, the group watches the videos and discusses the teaching interventions, while the advisor suggests points of further improvement. These discussions are also videotaped. Videotapes are used mainly to help student-teachers develop their teaching design and implementation skills. Attempts to influence the teachers' knowledge and beliefs will not be particularly effective unless these attempts draw on student-teachers' first hand experiences, enabling them to become aware of their own actions. However, videotapes have also been used with some of the student-teachers on one of the theoretical courses on Didactics that they attend at the same time. One of the goals of this course is to initiate the student-teachers into research experiences and to learn from them. Some of the student-teachers have chosen studies for the assignments in Didactics, where video-analysis was one of the research tools. Three cases will be presented here. In the first, the study of video focussed on the student-teacher's own development throughout the TPA, and the role that her advisor's comments played in the changes observed. In the second, the study traced the development of three student-teachers throughout the TPA. The student-teacher who did the analysis was one of the three cases, while the other two were members of the same group in TAP. In this case, the aim was to identify differences in the teaching plans and implementation of these three student-teachers in virtual and real teaching and to explore reasons for the degree of improvement in each one. The third study was undertaken by two student-teachers from two different groups, who collaborated and analyzed videos from these two groups. The focus here was on the advisors, their comments, and the emphasis given by each one during the group discussions. Results presented in student-teachers assignments showed that such kinds of research activities helped student- teachers a) to reflect on the experience of TAP, b) to become aware of their own development, of the differences which exist in terms of planning and applying their teaching interventions c) to report on the advisors' role and its impact on student-teacher development and d) suggest ideas for improving the system of Teaching Practice. The video analysis has proved to be a powerful tool for a) involving student-teachers in research activities, b) developing and encouraging student-teachers' reflective practice, c) gaining insights into their thinking as it is revealed in assignments, d) highlighting changes needed in terms of student-teachers' practices and in terms of improving the system of TAP.