Photo by: Joy Marie Photography on Wedding Chicks via Lover.ly
This doesn't fall under your formal bridesmaid-ing duties, but if you have these two extras on-hand for wedding-day emergencies, you'll automatically take home the Best Bridesmaid EVER trophy:
A sewing kit and a packet of fashion tape. You probably have both at home, anyway, so throw them in your bag. They could easily wind up being life-savers (or, at least dress-savers) for the bride and a bridesmaid or two.
Have you ever been at a wedding with a dress fiasco?
My friend Tatum went to get in her dress only to realize the zipper had never been sewn in. Feeeee-asco! (But she got sewn into her dress and looked gorgeous!)