Holy Matrimony is considered a sacrament in the Orthodox Christian church, and the service differs from that of other Christian churches. Firstly, it is split into two different parts: the Betrothal service and the Wedding/Crowning service. For a full rundown of the service, this pdf is a good resource ( http://ww1.antiochian.org/sites/default/files/CrownedBooklet.pdf ), but I'll briefly cover the different parts below.
The Betrothal service is where the bride and groom declare their willingness to be joined in marriage, and the priest prays for their future and blesses the betrothal. Couples do not exchange vows during Orthodox weddings but participate in the ceremony to recognize God uniting them through their marriage. The rings are exchanged to symbolize how the couple will compensate for each other's strengths and weaknesses. The wedding service then begins.
Orthodox wedding services are full of symbolism. After the betrothal service, the couple approaches the altar to offer their marriage for God's blessing. The priest joins each of their right hands to show their union and the couple maintains the bond throughout the service. They are further joined by crowns connected with a ribbon. The couple drinks from a common cup to show the sharing of their lives together; the joy and the sorrow. Finally, the priest leads the couple in a procession three times around the table where the cross and gospel book lie. It is a reminder to keep their married lives always centered around Christ.
During Orthodox wedding ceremonies, crowns are placed on the bride and groom's heads. They symbolize the crowns that await us in heaven and show the bride and groom as King and Queen of their newly formed family. Traditionally, the couple would wear their crowns for a week after the wedding. This is no longer practiced, but one last blessing is bestowed on the couple at a short removal of the crowns ceremony typically held following a vespers or liturgy after the couple returns from their honeymoon.