Love Me Love Me Love Me
If you have somebody do this for you, you will love her forever: Have somebody, even a paid somebody, tell you how beautiful you look pretty much non-stop for at least an hour before the wedding. No lying, just complimenting you on your best features and ignoring the bad ones. You can even give her a list. That way, no matter how fat and ungainly you feel in your wedding dress, no matter how much the way your nose looks bothers you, you will feel good about yourself at a time when you're not supposed to think about how you're looking. (That would be when you're taking your vows, in case you forgot the point of this whole exercise.)
The corollary to this is to ban people who feed you negativity from the dressing room, even if it is your mother or your Maid of Honour. Tough luck, Miss Butthead. No mean people allowed near the bride.