Don't correct your teachers in class. Rather than correcting them in front of all of the students, try to correct them in private. Either during the class while the students are working on something (ideal) or after class. Of course, this is something you should discuss with your teacher. SOME teachers like the students seeing their mistakes as well to show them that everyone can make mistakes.

Don't do things students can't do. If the students can't have their smartphones, you can't either. If your students can't eat or drink in the classroom, you shouldn't either. Check your school for the different rules the students and teachers need to follow. Also, try talking with your JTE about some things that are done in classrooms in your home country and see if you can introduce a bit of a culture lesson to your classes!

No leaning/sitting on desks or hands in your pocket. Things in Japan, including desks, should be treated with respect. This also means that you shouldn't push chairs in with your foot or toss things around. Use your hands to pick up and move things, and set things down gently and purposefully. You also shouldn't fan yourself. You must set a good example for your kids. If they can't fan themselves, you shouldn't either.

Be careful of certain hand gestures. This is referring to the good ole thumbs down. This gesture usually means no or something bad However, here in Japan, it's equivalent to "Go to hell." Instead, try making an X with your two index fingers or with your arms.