My son's b-day is in the middled of Dec so I never wanted to take away from his special day. The tree goes up and the house decorated the weekend after his b-day. We celebrate Advent so as of Dec 1 we hang our Advent calendar and the Advent wreath goes on the table. I always use a tablecloth and for the entire month of Dec it's green or red a Christmas color but not Christmas. Advent is a time of prayer and penance. The first thing I do is set up the Nativity set minus Baby Jesus, we wait until very late Christmas Eve or Christmas morning to put Jeaus in the manger. When my kids were little I would write little notes as to where to look to find Jesus, when He was found He went in the manger and there were hot cocoa and cookies waiting. The way people would put a candle in the window when they were expecting someone the lite tree is to light the way for the coming of Jesus. We don't/didn't decorate outside just a simple wreath on the door or window. Christmas is a religious holiday and we focus on that.