Okay, classroom management is an important point for our classes.
The teacher could talk or present a point from his subject by smiling, which can be elegant and encouraging, but turning into a serious look if there arise some misbehavior. What I mean is that smiling can be even classroom-managing, and it might show the teacher has the class-control in his hands. But if you think that a serious look is better, there you are.
Also politeness by the teacher, like thanking some small service by a student can sow a sane and upright classroom management. Plus the way we dress can help: it’s up to you, evidently, but an elegant “façade” may also help managing the classroom, and I’m now thinking of a teacher we had when I was some 14 years old. He was elegant and a smile was all the time on his face: he imposed respect, and he was kind and nice with us his students.
And he did nothing special for managing us as students. Even his lessons were interesting and said something special to us teens…; I mean you finished the lesson by thinking, Okay it’s been interesting to listen to him! He gave himself to us: that might be his secret, the secret of feeling happy! / Photo from: resized stan and car Prewarcar. The picture is a nice illustration for the post.