I'm not saying I never had bad classes, in fact I struggled my first semester with a large class of all girls. They were so cliquey and shunned a certain girl in class. I had no idea wtf to do. But I was able to figure out how to manage them in the next semester. I was lucky I have other teachers and manager who knew that class would be hard for a new teacher and they helped me get better with it. And the parents were helpful if you try to work with them. it might also be that I speak Chinese relatively well and could communicate with the parents. I also make sure that students and parents not focus on grades so much and on personal progress. I had kids come in with a 70 their first semester and get a 80 the next. They were below the class average but I made sure to let the kid and the parent know I was proud they made personal progress. And grades are not everything. Again. Be stern and strict in the beginning, you can always lighten up, but I find it's almost impossible to get stricter if you were not in the beginning.