I was trying to set the tone at a new school, so I went for smileys, because I was a new person there, and I wanted to set the "mood" for the year.
I had a lot of wall space, and a lot of door space as well, so I decorated a lot on the doors to the closets, and used that as bulletin board space.
I did we're all smiles in Mrs. ___'s room. I had a large Smiley face cut out, and put music notes around it.
And, I did smiley face cut outs with each teacher's name on them and the time they came to music listed, and above it read "So Happy Together"... (this was also a great tool to help me get used to my schedule.)
For behavior the wall said "Put your smile on!" and the rules were listed below.
For birthday wall I did " Keep Smilin', cause it's ______'s birthday!"
(I decorated that wall with retro looking designs...think 60's on that one..lol.)
My word pocket chart was also a large smiley face...lol.
And, I had a couple posters, one said "If you want a friend, be one", and had a smiley face on it...another read "Smile it's the first thing people like about you", and it had a gorilla smiling...and another one was Everyone smiles in the same language and it had children from various countries on it with joined hands.
My students especially the older ones LOVED the gorilla...lol.
If you need any other ideas, or if you want to bounce any ideas off of me, let me know. I'd be happy to help.