It should be relatively easy to put together a Hello Kitty costume for your little girl. Start by getting a set of white scoop neck pajamas, cut a white bath robe tie in half and glue it to the seat of the pajama bottoms (to act as a tail). In order to complete the costume, you will need fluffy slippers, white mittens, a white cat ear headband, a big red hair bow, and white and black hypoallergenic face paint. Dress your daughter in the pajamas, slippers, and mittens. Place the cat ear headband on her head, and tie the red ribbon in her hair. Finally, paint her face with white hypoallergenic face paint and add black whiskers.