To decorate a house for Christmas, you can start by hanging up lights outside the house. You can also put up a Christmas tree and decorate it with ornaments and lights. You can also put up stockings, wreaths, and other festive decorations around the house. You can also play Christmas music and have a Christmas dinner with your family. Don't forget to put up a nativity scene if you celebrate the religious aspect of Christmas. Lastly, don't forget to spread Christmas cheer by giving gifts to your loved ones.