Hmm i don't get what everyone keeps mentioning Misa Amane as she has 'Shoulder' length blonde hair not waist length.
Anyways i have a waist length blonde wig too and i had no idea what to do with it
Ruka Souen from Vampire Knight(her hair is kind of waivy, what i did for this cosplay is braid the wig, hair spray it and put in one of those zip lock bags and leave it for a while, and i will be all nice and waivy
Chii/Freya from Chobits(Though you would have to make/buy the ears and the hair spoils. And Chii is rather petite. I would suggest Freya as she tends to wear black gothic clothes which would shape your figure.)
Belarus from Hetalia
Alice from 'Alice in the Country of Hearts'(Or just Alice in wonderland)
And these are all my suggestions.(sorry for the long response XD) I also suggest you go to the anime characters database you will get lot's of ideas from there (: