I've collected a few inspirations that may help in making a peacock wedding theme work.
Reception table: I like the forest-woodsy vibe I'm getting with this table. Reminds me of a peacock's natural habitat: nature.
Bride's hair accessory: I prefer this as a bride's accessory seeing that the colorful peacock feather would certainly stand-out against the white/cream/champagne (or any other usual light-color wedding gown). Besides, who better to carry the theme if not the bride, right?
Source: AzureTreasures (Etsy)Bridesmaid jewelry: I just love the color in this necklace. Perfect for your bridesmaids' to wear; just a simple accessory that represents the wedding theme and happens to be fab, too.
Source: Good Earth Floral Design StudioBride's bouquet: Too pretty not to post and if you are already wearing a hair clip made of peacock feather, the green and purple combination in the bouquet would be just right.
Source: CleopatraKerckhof (Etsy)Wedding guest: If you want a statement accessory and the wedding you'll be attending has a (you guessed it) peacock as wedding motif, you'd fit right in with this necklace.