Being a bridesmaid is honoring yet there are commitments that come with this. You're the bride's best friend, so you're "the chosen one" - your friend's tying the knot and it's a very unique occasion certainly, but there are so many things to take care of, that you don't know where to start. The important thing is that you're supposed to glow, not for yourself - but for your friend - concentrate all of your actions around that and you should be alright!
The dress - this is practically the toughest decision. You'd like it to be not too fancy, but still classy; think about the general picture when you decide on this, and discuss with friends - and especially with the bride (after all, it's her party - she should be the happy one). If you want dress examples, just Google them - you'll get hundreds; you can even have the pleasant surprise to find nice dresses under $100.
The shoes - should necesarely go along with the dress - from every point of view (color,appearance and so on). Here I'd like to remark it's an absolute must that you feel very pleasant wearing them - you don't want anything ruining your mood - so take care when choosing them.
Choosing the hairstyle can be a real challenge, but that's when the Internet comes in again - it saves you a ton of time, since you can always Google hairstyles, print them out and take them to your stylist. Depending on your hair's length, there are many variations that you can choose - but then again, you have to make sure it fits the dress, shoes and so on.
Last but not least, since you're the bridesmaid - you're best suited to organize the bridal shower party. It's very recommended to organize it secretly to surprise the bride 100% - so the effect will be guaranteed. Things to have on your mind: theme, the supplies, invitations, games, and so on - it's not an easy task at all.
Whatever you'll choose, everything will work out just great if you do things with all your heart and driven by the idea to please your friend. When you'll realize that it's all about giving and not receiving, everything will start to blossom for you and for your friend. Here's to your success!