Dancing is never as much fun as it is during a wedding. As the maid of honor you will have special dancing priviledges. You should enjoy them.
Dancing at a wedding reception usually begins after desert has been served and eaten.
During the Bride and Groom's first dance it is a good idea for you to stand with the other members of the bridal party. You can clap and cheer when they are anounced. You can also take photographs or anything else that would be seen as encouraging.
You will dance your first dance with the best man. This may be during the third song if the parents of the bride and groom have their own dance or it may be during the second song if the family situation is complicated. Either way, follow the lead of the best man.
Traditionally, the bride and her father have a dance. At this time you should not be dancing.
Their may be a tossing of the bouquet. Sometimes the bride will have a special bouquet made for this purpose so that she can preserve her bridal bouquet. If this is the case the maid of honor is usually responsible for preserving the bridal bouqet.
During the tossing of the bouquet, the maid of honor is usually part of the crowd trying to catch the bouquet. A matron of honor is exempt from this. The maid of honor has no special requirements during this time. You are not required to stand front and center although the other bridesmaids may place you there.
Reference: Wedding Etiquette