Be jolly

This is perhaps the most important rule of all. In the end, Christmas is not about spending enormous amounts of money or spoiling your children,parents,grandparents,significant other. Rather, its about coming together and celebrating all of the good parts of life. The best thing you can do to prepare for Christmas is just be happy. Its the one time of the year where you do not have to hate on humanity (which is what I do 95% of the time). Take advantage of it. Its the most wonderful time of the year, after all.