I will be switching from teaching middle school general science to teaching physics at a local high school. I’m looking at how I should change my classroom management strategies to fit high school/older students. 
—M., California
 
It just so happens that I made this exact same switch in my career! High school and middle school behaviours can be different, but some general strategies are applicable to both.  

I found it useful to create an image in my mind of what my perfect classroom would look like: what the students were doing, how they were interacting, and what I was doing. This image would guide my decisions about anything that happened in the classroom. The overall goal is to create a consistent environment that is conducive to teaching and learning. For instance, I knew I wanted every student to feel safe and willing to contribute to the class, so I dealt firmly with any teasing, bullying, put-downs or inappropriate jokes.  

Being well prepared is important because fumbling around during a lesson can result in unwanted behaviours. I found that backward planning—planning the end results or outcomes of your unit first, then designing lessons to get you there—helps you envision what comes next and enables you to deal with unexpected issues or interruptions quickly. So if the internet goes down and today’s lesson won’t work, you will already have a follow-up lesson in mind.

Behaviour issues have a cause, and you should investigate what may be causing a student to act out. Knowing the cause may not correct the misbehaviours, but you will have a better understanding of why they are occurring.

With high school students, you will get more adult behaviours and situations, both good and bad. Nonverbal communication will tend to work well for most students. Rather than group discipline or a public redressing, I would deal directly with a student’s misbehaviour by having a one-on-one conversation with them (usually outside the classroom door). Be direct and don’t lecture.  

Hope this helps!