Beginning of Year
We like to start by reading "A Fine, Fine School" and discuss and write about why our school is a fine, fine school. Your theme could be "It's cool to be in school".
Also, you could have an "Under Construction" theme and have everything with a construction theme. Teachers/Children could wear plastic construction hats and have the classrooms decorated as such with many bulletin board ideas such as "First Graders are Great Workers".
Another idea could be about summer (if you start school in August). You could have an ocean theme--The hallway theme could be entitled "Sea of Learning" and have each teacher do different ocean animals and decorate as such. You could have the hallway decorated as a big ocean with water, seaweed, sand, etc.
Yet another could be the jungle. Hallway for first grade could read "It's a jungle in here" or "We are WILD about First Grade". Have different animals for each room and decorate with leopard prints, etc.
I also like the happy face theme. "We are happy to be in First Grade". Have smiley faces everywhere with various bulletin board decorations. "First Grade is something to Smile about", "We love First Grade".
The farm is another cute idea. Make the hallway a barn and enter through the barndoor. Each teacher can go anywhere with this one. Bulletin boards could read "We've picked the Best First Graders" and have a cornfield with the children's faces on the corn or "First Grade is Overall the Best" and have little overall's on the children's picture on a bulletin board.
Frogs (ponds) are also a good grade level theme. "Hoppy to be in First Grade". You could have lily pads everywhere with pussywillows on the walls. We really love the pond theme.
I hope these ideas helped...