6th grade is a wonderful age.
6th graders start the year as kids, and morph over the course of the year into adolescence. By the time they start 7th grade, they are in full blown angst. At least, in my experience. :wink:
I have the same rules for 6th graders as I do for any other age child:
Be safe, be respectful, be responsible.
Like any other age student, they have to be explicitly taught what safe, respectful, and responsible look like in each setting that they will encounter in school: classroom, hall, cafeteria, gym, playground, bathroom, library, etc..
Then they need to review those norms regularly.
Like any other age student, they respond well to an abundance of positive reinforcement, correction, and consequences when necessary.
Check in with the middle school forum as well, if you haven't already, since 6th grade is often part of middle school rather than elementary.