Be prepared to speak English if you are going for a job where you will be teaching English. You also need to know a lot about what you will be teaching, what methods you have of teaching your subject , the types of classroom management strategies you employ. You need to be familiar with the policies of the school you will be teaching at. If you have worked as a teacher before, I suggest that you take examples of students' work with you to your interview and any references or commendations you have received.