When you are a teacher, it becomes even more difficult to become perfect for all your students. It’s clear, that we all are different, so your students are, and each of them has his own learning style. When your teaching style suits a learning style of your student, you will definitely become his best teacher ever. This is like to be on the same wave with someone. But it’s obvious, that all your 30 students (or 20, or even 10, it doesn’t matter actually) will never have the same opinion about your teaching methods, so, misunderstandings are impossible to avoid.
Your students can have problems, bad days, stress, or even depressions as well. If you see that some of your students start to study worse, have no desire to do all schoolwork you give them, and just want to give up everything, do not be in a hurry to argue and tell them about how bad or lazy they become.
Students just don’t like when their teacher starts behaving like a student himself. Stay professional, help students with schoolwork, listen to them, talk about their lives, but remember who you are. Even if you are a young specialist, and you are almost of the same age with your students, there is no need to use all those slang words (even if you use them in your everyday life).