Photocopy pictures from Mother Goose books and glue them onto posterboard. Place them around the room and see if guests can figure out which rhymes they represent.
Get small stuffed sheep and other nursery rhyme animals and intersperse them among the food items in the serving area.
For streamers place a clothesline or string along the ceiling, as you would steamers. Cut "mittens" from colored construction paper and clip with clothespins for the Three Little Kittens mittens
Get a vase of flowers for a centerpiece, either with the food or at the gift table. Wrap a piece of colored paper around the vase and secure. Wrap a smaller piece over this and secure and draw the outline of one or two pockets on the paper. (Ring Around the Rosie, Pocketful of Posies)
Hang stars and a moon from the ceiling with fishing line. Glue a large clipart of a cow onto the moon.
For little touches, hang spider webs for Miss Muffet, set out pumpkins for Peter Pumpkin Eater and shoes for the Old Woman Who Lived in a Shoe.