School principals are responsible for supervising STEM teachers, yet many principals did not teach in the STEM fields and have limited training in STEM content, process and practice. This presents a challenge for principals when they observe STEM classrooms and provide feedback to teachers. In this paper the authors describe a study about principals' views of STEM classrooms and the observational feedback principals provide to those teachers. The results of the study suggest principals need a deeper understanding of reform minded STEM process and practice, and alternative approaches to providing teachers with observational feedback. Building on the results of the study, the authors present a collaborative model (Innovating Teaching and Learning Leadership (iTALL)) for preparing pre-service principals and pre-service STEM teachers and describes training in the STEM process and practice. Observational exercises are discussed and changes in observational protocols when conducting classroom walk-throughs are described.