A lot of today's traditions regarding the bride can be traced back to medieval times, and even further.
The dress wasn't necessarily made for the occasion. Often the less rich girls just wore their finest garments. White was not the usual color for the gown, instead the fabric was bright and colorful. Red and blue were amongst the finer colors and later black also became a sign of wealth. Some dresses were made of silk, while others were less refined.
On her wedding day the bride was allowed to let down her hair and flowers were braided into it. If your family was rich you would also wear the bridal crown. After the ceremony the bride should cover her hair with a hat or fabric because it was considered to be indecent for a married woman to have loose hair.
Many brides were younger than their husbands - so my boyfriend and I will fit right in :) - Women of noble birth were often the only ones to turn 20 before their wedding.
The bride herself was normally considered to be a part of a bargain and marriage was a way to establish your social position. The tradition of the father giving away the bride was a very literal thing in the middle ages. He decided who he wanted to give her to, and it was the father who paid for the wedding. At the ceremony he also had to answer on her behalf.
When she received her new title as a wife her new husband would give her, the key to the house and the chests, along with a knife as a sign of her status.