Besides the obvious things that are illegal or immoral, it's always good to remember that there really are things that we might think about doing that we really shouldn't include in our classes. For example, it's not a good idea to ask your only Jewish student to explain the Holocaust or your new immigrant student to describe life in his or her country of birth. It might seem like a good idea at the time, but it's not.
It seems simple, but I know one or two teachers who curse regularly in class or fail to follow through on discipline. If those don't apply to you, check out number 10. It applies to everyone. This article might also make a good discussion starter for a team meeting or professional development exercise.
I'm definitely guilty of trying to change one student's behavior by focusing on another student's positive behavior, but it really isn't fair to either student. This article does a great job of explaining why some of these things really shouldn't be said. I found it very helpful.
Okay, I know, we've all been guilty of it, but taking forever to return work to the students is definitely one thing they hate. I like to think that if I explain the delay it helps alleviate any anger. However, that's one of the five things that I try to avoid.
Sometimes it's really hard not to engage a student who is disrupting class, but these gentle reminders will help you navigate those moments and provide you with what you should do and remind what you shouldn't do. For example, react in a way that allows the student to save face is great advice--especially for those tricky middle-school students.