Review and consider your classroom rules. My best advice is to keep them simple and few and if you want to go into detail, let the students collaboratively write out the details in a google doc or using post it notes as you talk about what kids should and shouldn't do in the classroom. It is great to talk about these things up front because you will understand the "pet peeves" that drive kids crazy about each other (saving yourself time.) I find that spelling out my bare minimum and involving kids in the detaiils gives them ownership.
As you talk about Classroom Rules, you might want to use this hilarious Sesame Street Parody - "Share it, Maybe" - a parody of "Call Me Maybe" -- just so funny. (All they need is a baseball team in the back.)
Great page on Classroom management and Class Rules from Jerry Blumengarten. If this is an issue for you and you really need a TON of ideas, Jerry is one of the best curators on the web!
When looking for graphics like for Classroom Rules, I like to do image searches on Google because you can usually find some very brief summaries. Here are some short ideas for those of you working on your wall posters now. Simple is better.
If you're on pinterest and use the hashtag #classrules in the description it will show up on this lovely board. This is an example of how hashtags can do incredible things on Pinterest (like on Twitter.) Now is the time to share these.