It does help to get an agency and the work you want in the bridal industry if you have a photo of yourself in a dress.
However there is some self promotion you can do/ try:
Mail photos to photo editors at Bridal magazines.
Read bridal magazines and find out who is shooting the editorials in the magazines, before the editorial you can see the photographes name. Google them and see if you can get a test shoot.
Reach hairstylists and jewelry designers who design for the bridal customer and see if they need a model. Might be able to get some test shots or experience.
Pitch an actual wedding photographer and try to get some test shots.
Focus on getting a smile and energy shots, photos that show your personality. You do not want to get too stuck in the fashion sector that you miss out on opportunities so although you are tall you also want to show your personality in photos and also not make your photos TOO fashiony, more natural is best.
Many girls think posting their photos on websites like Myspace or Facebook is enough to call themselves models, it is isn't. Do not market yourself with your Myspace account, it is better to market yourself with a print photo, or make a compcard at compcard.com or send a jpeg, not Myspace!