Establishing expectations
When the school year rolls around again, we all will be getting a new crop of students on the bus. Some of these will be riding on your bus for the first time due to graduation from elementary, junior high, middle school, etc. If early on they start misbehaving, and some surely will, I have had success in modifying their behavior by telling them that they are not on the little-kids bus anymore. Now they are on the big-kids bus and should behave accordingly. It establishes expectations that they will have to observe and learn from students in upper classes. Generally the older students are better behaved and are a good role model.