I write about this tradition as an attempt to do just that. As it is, even for those of us who see the tragic irony of commercialized Holy Days, it seems like the most we ever do about it is remind people to "Keep the Christ in Christmas." It's a catchy slogan, but Advent has the potential to be so much more powerful than simply trying to remember to wish Jesus a "happy birthday" while we stuff ourselves with gifts and feasts. (Not that I am at ALL opposed to Christmas meals and presents.)
The word "Advent" comes from Latin and means "coming." It's a translation of the Greek word "parousia," which is the word used in the New Testament to refer to the second coming of Christ. So rather than being a single Holy Day, Advent is a season of preparation, leading up to Christmas. Thus, during Advent we prepare to celebrate and commemorate the birth of the Savior and the wondrous miracle of our Lord's Incarnation. But far from being strictly an object of remembrance, this Savior lives and has promised to return. So while we remember the first coming, we prepare for the second.
The practical side of it is fairly simple. During the season of Advent, we center our devotional life around these two "comings" of Christ. In our reading, in our prayer, in our giving, in our volunteering, in our church-going, and in anything else we do as an act of faith, we keep our focus on Jesus as Incarnate God and Coming Lord.
Advent is a time for both solemnity and joy, hushed reverence and eager expectation. As though standing in front of a campfire, we feel the cold of winter at our backs, while the holy flame heats our hands and faces. So I invite you, come stand by the fire. This hopefully served as a good primer, but I encourage you to do further research about the meaning of Advent, join in the tradition, and maybe even start some traditions of your own. I intend to write more about this in the weeks to come.