The Feast of St. Andrew has always been closely associated with the beginning of Advent as it usually falls shortly after the First Sunday of Advent. In light of that fact, for at least the past century a prayer was developed as a daily preparation for Christmas and took November 30 as its starting point. It is sometimes called the Christmas Novena, St. Andrew’s Novena, St. Andrew’s Christmas Prayer, or the Christmas Anticipation Prayer.
It is a beautiful prayer that focuses on the moment of Christ's birth and can act as a great meditation for Advent. The prayer is customarily prayed 15 times a day, but in reality it can be prayed once a day or whenever you remember throughout the next month.
If you are looking for a prayer to pray each day of Advent to prepare your heart to receive Christ, try the "Christmas Novena."
Hail and blessed be the hour and moment
In which the Son of God was born
Of the most pure Virgin Mary,
at midnight,
in Bethlehem,
in the piercing cold.
In that hour vouchsafe, O my God,
to hear my prayer and grant my desires,
[here mention your request]
through the merits of Our Savior Jesus Christ,
and of His blessed Mother. Amen.