In this paper, we examine the importance of building instructional units that incorporate metacognition intent processes that contribute to the development of geometric thinking. We show that the implementation of metacognition processes in the initial stages of constructing tailored instructional units will improve students' geometric ability. The study was performed on middle school mathematics teachers of the ninth grade. The experiment we conducted shows that building instructional units that incorporate metacognition intent benefit learning processes on two levels: First, in the subject matter. Second, they contribute to a deeper understanding that improves student's ability to connect related subjects to mathematical geometry. moreover, we will present a practical model that incorporates different aspects that could operate a guideline for middle school mathematics teachers.