So I have been to many an ADPi wedding and the most common traditions I've seen: 1) make sure the bride has something blue
or add some violets to her bouquet 2) all the ADPis in attendance get together at the reception and circle around the bride and serenade her with ADPi songs... which song will likely depend on those that your/her chapter used but common ones I've heard are "God Gave the Wisemen" or "When You are an Alpha Delta"...
And for those who have been through Jewel Degree, a common verse used in weddings is a theme in Jewel Degree
and a framed copy of it was given to me by a sister for my wedding (which of course my husband didn't quite understand the hidden sentiment but I got it immediately and loved it!!!)