My teaching method for Mathematics and Physics in preparatory classes for the Grandes Écoles (Sup and Spé) is based on three key requirements: conceptual rigor, methodological mastery, and competitive exam preparation. A graduate of the École Normale Supérieure, an agrégé in Physics, and a Doctor and Senior Lecturer in the Epistemology of Physics, with extensive experience supporting students in preparatory classes, I first focus on consolidating the theoretical foundations (definitions, structures, hypotheses, and the relationships between concepts) to avoid superficial learning. I then emphasize problem-solving methods: careful analysis of problems, selection of relevant tools, structured writing, and time management during exams. Finally, I adapt the work to each student's profile, providing demanding yet supportive guidance aimed at developing autonomy, computational skills, critical thinking, and confidence—essential qualities for success in competitive exams.