Advent is a time to prepare for the feast of Christmas. Advent means "coming." As we say in the Mass right after praying the Our Father, "Deliver us Lord from every evil and grant us peace in our day. In your mercy keep us free from sin and protect us from all anxiety as we wait in joyful hope for the coming of our Savior, Jesus Christ."
This "waiting in joyful hope" lies at the heart of Advent. The readings of the first two weeks focus on the second coming of Christ and his judgment so we can prepare our hearts for his return. At the beginning of the third week, that Sunday is also called Gaudete Sunday. Gaudete means Rejoice! We move from a time of preparation and penance to a more joyful time of rejoicing and readiness. Christmas is coming!
Christmas is coming, but it is not quite here. The readings shift to focus of prophesies of the birth of a Savior, a Messiah, a Christ.
The best recommendation I've heard regarding Advent is to think of it as the Church does! It is the beginning of the Liturgical year, the Church's New Year! And just as we make resolutions to lose weight or stop smoking or turn off Oprah, we should make Advent resolutions. We might decide to learn to pray with the Church using the Liturgy of the Hours in some form. Or maybe go to daily Mass more often. We could make a commitment to contribute to the food pantry every month, or to volunteer at on of the parish's social ministries. Advent is the perfect time to examine our lives and ask "Lord, what do you want me to do, to be?"
Try waiting until at least to the third Sunday of Advent, Gaudete Sunday, to string lights or put up the Christmas Tree or play Christmas music. The commercial, retail world will overwhelm you at times; but the more you enter in to the time of waiting in joyful hope that is Advent, the more joyful your Christmas season will be. For the Church celebrates Christmas for more than just one day! It lasts from December 25th all the way to the Feast of the Epiphany on January 6th. Now that's a time of rejoicing in joyful hope!