Take the color into mind. Blush and taupe are hot bridesmaid dress colors right now, but they don’t suit every skin tone. They can wash some people out. If you’ve got a range of fair, olive, and dark skin tones, make sure the dress color flatters all. You can work in a two-color palette, to please everyone (think pink and a darker coral).
Take care of season weather. The date of the wedding is probably a big factor in your décor—fall tones and apple centerpieces for October, peonies and spring colors for May—but the time of day matters, too. Black dresses could be perfect for November but a little forced for an outdoor, mid-day ceremony.
Be flexible (to a point). Most bridesmaids would like to have some input on what the're wearing, but too many opinions can make the whole process miserable. Look for brands that offer similar dresses with different necklines, for example. You can pick the color and fabric; each girl can decide on the style most flattering for her body type.
Remember, it’s your day. Don’t succumb to pressure to make everyone happy. You should keep an open mind and be understanding, but your bridesmaids are there to support you and should (ideally) work with your vision.