The bridesmaids, the mother of the bride or the maid of honour usually
coordinate their outfits with the bride's look. One possibility would
be that the pattern of the bride's dress can be found in the dresses of
the wedding guests - in a different colour obviously!
A lot of brides shop take their bridesmaids, maid of honour and mother
to look for their dress and use this as an opportunity to determine a
coherent style for their female entourage.