One of the first issues I've had, which affects every aspect of the classroom is learning how to manage the students' behavior effectively. If a teacher does not have effective strategies, it can cause strain on student-teacher relationships, be a constant frustration for teachers, and cut into class time. At Sauquoit Valley Elementary, they train all school personnel in 1-2-3 Magic, a program designed for disciplining students. I've found it to be very successful. The program I went through was an extensive all-day training program, but you can view the brief overview of the program here.
As a brief overview of the program, each time a student acts out or does something he is not supposed to do, the teacher counts up a number. So, if a student shouts out in class, the teacher says "Johnny, that's 1", then continues with the class. If he then does it again, or acts out in another way during that class period, the teacher says "that's 2", and if it happens again, "that's 3. Take 5". The student then must take a time out for five minutes. This method makes it clear that the student has done something wrong, but wastes minimal time, and leaves little time for conflict. The student may be embarrassed, and is then forced to sit and think for a 5 minutes. When they rejoin the class, the teacher thanks them for joining them again and continues on. This avoids the escalation that may occur when a student is frustrated and wants to fight back. There is no power struggle. I've found this method to be particularly useful and effective for all these reasons.