The children participated in establishing our rules.  We created lists of rules that we have in school, in the cafeteria, at recess and in the hallways.  We used a carousel activity where they moved around the room and added to previous ideas.  If they agreed with a rule on the chart, they checked it and then added any new ones.
Here is one of the charts the children created.  
We then narrowed down our classroom rules:
1.  Follow the Golden Rule.
2.  Be a good citizen and show respect. 
3.  Always try your personal best!
 
 

