The season of Advent, a season of waiting, is designed to cultivate our awareness of God’s actions—past, present, and future. In Advent we hear the prophecies of the Messiah's coming as addressed to us—people who wait for the second coming. In Advent we heighten our anticipation for the ultimate fulfillment of all Old Testament promises, when the wolf will lie down with the lamb, death will be swallowed up, and every tear will be wiped away.
The spirit of the worship service and the visuals of the worship space change dramatically from the Fourth Sunday of Advent to the celebration of Christmas. White, yellow, and gold are the colors of Christmas, and many visual symbols and images—angels, candles, the star of peace, shepherds, the manger, and so on—come to mind. Christmas carols have their own built-in spirit of celebration.
from The Worship Sourcebook Second Edition, p.427 & p.471
See parts D and E of The Worship Sourcebook Second Edition, pp. 427-498, for sample prayers and other worship resources for each act of worship during Advent and Christmas, including the Call to Worship, Opening Responses, Confession and Assurance, Prayers for Illumination, the Lord's Supper, and Blessing/Benediction.