It’s important that your bridesmaids know what shade of color their dress should be and the formality of the wedding.
I write shade instead of color because each color comes in a range of shades. For example, blue can range from navy to royal to sky blue. Pink can be fuchsia, bubble or pale pink. You can give each ‘maid a swatch or paint chip or send them images of dresses in colors you approve of so they get the idea.
Formality is important because it will dictate the dress’ hemline. The more formal the wedding the longer the hemline. You also want consistency so giving them a guide as to what length is okay will ensure a more cohesive look in your photos.
Make sure each girl knows if her arms need to be covered or not for the ceremony. Some houses of worship may ask for arms to be covered, which means no strapless dresses.
If you’re still nervous, tell them that while they can choose their own dress you have the right to veto it. Plan some shopping dates or shop together online and you’re sure to find something that makes you and each of your bridesmaids happy.