The introduction to teaching is critical for novice teachers. Near the end of their master's program, students of Business Education and Development in Austria spend one semester at an assigned school. They are introduced to teaching, while being assisted by peer students, mentoring teachers, and a companion course. Mentors receive special training and preparation in advance, thus contributing to a high quality mentoring program. The program is organized threefold: (1) providing feedback, (2) opportunities for reflection and (3) career orientation. The purpose of this paper is to assess key elements of successful mentoring programs and to question which competences of mentors contribute most to the success of those programs. Between 2012 and 2015, 188 persons (student teachers and their mentors) responded to an online survey at the end of their mentoring program. Additionally, data from a study (1,245 questionnaires) regarding the student teachers' perception of their own competence was utilized, allowing for a comparison of student teacher confidence in their abilities before and after the mentoring program. The present results provide insight into the key elements of successful mentoring programs; both from a student teacher's and mentor's perspective. During the semester, students showed an increase regarding their self-perception of their professional competences. It was found that students and mentoring teachers valued feedback after each lesson more than feedback in regular meetings. Opportunities for reflection (e.g. exchange with peer students, learning diaries) were considered helpful. The mentoring program helped students to decide whether to become a teacher or not.