The bridesmaids provide support to the bride, including helping with the bridal shower, writing the gift descriptions, passing out cake to the guests at the shower, assemble the invitations, and any other tasks the bride wishes to assign. The best thing the attendants can do is be response to the bride's needs, follow-up on any requests, and be present. <br />
Assemble a "bridal emergency kit" for just in case... Ideally, this kit should contain a toothbrush and floss, breath mints, spot remover, band-aids, tampons, extra nylons, bobby pins, a needle and thread, fabric tape, a comb or brush, pressed powder, neutral lipstick and whatever else you think the bride might need. [weddingchannel.com]
To suck up to the bride and make her look good in comparison. <br />
Honestly. That's their role. Ever been a bridesmaid?
The chief bridesmade, or maid of honor is there for the bride from the engagement to the limo ride to the airport for the honeymoon, the regular bridesmaids are just there to support the bride, help out at events (showers, wedding dress shopping, etc) not make a burden of themselves, and hide anything that may go wrong on the wedding day (like a gallon of red nail polish accidentally spilled all over the honeymoon suite bathroom!)
To get drunk on her hen-night if old enough, younger ones to look cute in photo's!
The Bridesmaids should help the Bride by offering opinions that she must, as the Bride, reject. In this way the bridesmaids can help steer her away from choosing things like dandelions for the bouquet or having the flower girl throw grass clippings to make the wedding more "green".<br />
The bridesmaids should preempt these ideas by suggesting them first. With this responsibility comes wearing a peach taffeta dress, but consider for a moment that if you don't wear it she might!
Make the bride look thin by contrast.