I firmly believe that practice is the key thing to achieve a high grade in all sciences and math. But I also think that a class should be relaxed and laid-back with no tension between the teachers and students for a relatable experience.
In my lessons, we will firstly go through the topic and I will teach it to the students for understanding then we will move on to topic questions to fully grasp the entire topic. Then when that is done, we will move on to another topic repeating the same process. By the end of the syllabus we will start doing past papers and will do them over and over to see what is being done right/wrong and correcting that until we are fully prepared for the day of the exam. This is the system that I myself have abided by and achieved an A*AA in chemistry, math and physics and has allowed me to study Mechanical and Electrical engineering at the University of Edinburgh. However, this system can change depending on the needs of the student and what they want at the moment as not every student is the same so they not will not be treated the same way.