Each student learns in a different way so sometimes the format of teaching can vary to suit each student. One of the most effective ways I have found in my experience is to review the lesson all together, then target the areas that the student doesn’t understand / needs help with. Then we would go over those areas again, maybe in a different manner, to ensure that the student understands it fully. Also, it is helpful to have some small quizzes once in a while to assess their knowledge of the lessons.