This is an excellent example and one a lot of teachers, not just band directors, forget. Model the behavior you want to see. When a student walks into your office don't multi-task. Give them your undivided attention and then when you ask them to do the same in rehearsal there is understanding of how that looks. Don't blow up on a kid and then wonder why they blow back. (this was one I saw so many times in inner-city settings. The kids bite back. Doesn't mean you don't have standards but I could handle the toughest of kids in the hallways that others couldn't because I didn't bully them yet they complied). Don't have side conversations during rehearsal and then wonder why they are having them while you are working a different section. Stay off your phone on the podium and then you don't have to wonder why they have theirs on their stand. Don't walk around with your cup of coffee in rehearsal telling them how important it is to you while you tell them no food or drink in the band hall. MODEL the behavior you expect of them. One of my biggest things was I never asked a kid to do something I wouldn't do. The simplest was never asking kids to move chairs to set up the band hall. I would start moving chairs and almost instantly a few students would ask if I wanted help. After about a month of that they were doing it on their own. Oh, and be on time! Always, be on time, start rehearsals/concerts on time, and ALWAYS end on time. I never ended early because rehearsal time was important. I always told the kids if we didn't need rehearsal I wouldn't schedule one. I never ended early but I NEVER ended late.