Hang posters in prominent places throughout your classroom.  Moving them from place to place from time to time is also a good idea.
 

Refer to the posters often with regard to ongoing classroom issues as they come up.
 

Find a moment, each day, to point to a poster and inquire of your class -- "Where have you seen evidence of this poster today?"
 

Before your class goes out to recess, ask them to "be on the lookout for evidence" of a particular poster.  Don't forget to follow-up on this when they return from recess.
 

Use thumbnail images of posters in your classroom newsletters to parents.
 

When there is a conflict between class members, ask the participants to list the poster(s) that apply before sitting down to resolve the conflict.  Just this simple step can go a long ways toward resolving the conflict.  Encourage your principal to use this strategy as well in his/her dealings with students.  Have your principal contact me for a set of mini posters for their use if I haven't given them a set already.
 

Use posters as writing topics.
 

Use posters as topics for partner/small group oral presentations.  After practice, followed by feedback from the class, and more practice -- video tape the presentations.  Share these presentations with other classes.  Develop an open house presentation.