Little boutiques - the kinds of places you can hardly find without walking around your nearest city for awhile or through word-of-mouth. I did bridesmaid dresses with a friend awhile ago and honestly we went to all the big department stores and we saw the same dresses, or lookalikes, about 50 times. Once we hit the boutiques on the outskirts of the city we found stuff that had the most unique detailing and different little touches. Bigger places tend to source from the same designers, where as smaller ones have those one-off pieces you never see again. Just make a day of checking out your local area for a few & good luck :)