I used a 12" green styrofoam wreath, a bundle of "Fur Fun" green yarn, and about 1/2 a yard of fabric ribbon flowers, and fabric pins(all found at Joann Fabrics).
Wrap the yarn around the wreath, and use pins to add the flowers. Pretty darn easy and straight forward. I had a small wooden birdhouse that I used for extra decoration, but really anything can be used.