Just used black headbands. Cut the ears out of felt (from a template from the MMCH website) folded in half and hot glue them together on to the band. paint some styrofoam balls for the mickey and minnie head centerpieces.
Did this but not just with Mickey heads. Printed and cut out Mickey and friends figures, also Minnie's bow, Goofy's hat etc. I'll upload some photos sometime later on my board "Done That" / Mickey Mouse party ideas