Student-teaching internships in a teacher-preparation programme are a significant way for teachers to gain practical skills and transfer their textbook knowledge into classroom practice. One of the outcomes of student-teaching internships is that pre-service teachers can observe experienced teachers' teaching pedagogy and strategies for implementing their skills. The purpose of the research study reported on here was to explore how pre-service teachers acquire and improve their teaching pedagogy through the peer observation training model at the secondary school at which they intern, with a focus on pre-service teachers with an interest in science, technology, engineering and mathematics (STEM) teaching. The results indicate that most of the participants could learn and improve their teaching pedagogy through the peer observation professional development programme -- particularly young teachers without significant work experience. More importantly, the research proved how a peer observation cycle programme may apply to different educational systems with similar structures internationally, particularly in former European colonised countries with similar backgrounds.