To decorate a bathroom for Christmas, start by hanging stockings on the wall or behind the door. Then, add a Christmas-themed shower curtain and a bath mat with snowflakes or other festive designs. Add some festive soaps and hand towels, and place a small Christmas tree or a few poinsettias in the corner of the bathroom. Lastly, hang a wreath or some garland on the mirror and add some Christmas lights around the room for a cheerful and festive atmosphere.