The wings:
My hottest tip for fairies is to make your own wings.
The dress:
This is up to you and whatever fairy you want to be. For a water fairy, choose something flowing. A fire fairy will call for a shorter skirt. Visit your fabric store and look for specialty fabrics. Get a 1/2 yard and then play with it. Tie it on your waist with some ribbon, make wrist bands out of it, attach it to a hair clip...the sky is the limit with a fairy costume.
An easy way to make a fairy costume is to hack up an old prom dress.
The shoes:
Again, it's up to you. Boots on fairy's are very cute. You can wear leggings with heels...whatever you like!
The makeup:
Glitter here, glitter there...glitter everywhere! Heavy eye makeup, lipstick, even lots of blush is good on fairies.
Accessories:
Armed with bubbles, you can add some fun to the party. You can add fake flowers and leaves to a bubble bottle to make it match your fairy theme. Turn a bottle of bubbles into a matching accessory.