The best way to get her to react in a way that will end the teasing and win her more friends is to do some "dry run" practices to get her "bully proof humor" in resilience mode. By practicing a few canned responses in non-emotional role play scenarios, she can remove the vulnerability she feels when her looks, interests, intelligence, or character are challenged.
You as a parent, can make a list of the top 4 or 5 things she is most commonly teased for that she could be able to turn around with a positive and infectious humor. When you guys are in non-threatened down time (like riding in the car, cooking dinner together, getting ready for bed at night) you can run through one or two role play situations with her in reverse (have her be the bully and you be her) That way, she can not only memorize the words you use, but your confident and easy body language as well as happy and unintimidated facial expressions in order to diffuse the stressful moments she will undoubtedly face a million times before her peers "grow out of it".
Let her know that kids often "tease" or "joke" about things that make them feel uncomfortable or vulnerable about and by reacting to what they are feeling rather than saying, she can make friendships stronger and prevent herself from feeling victimized by every kid that doesn't know the "right" way to express emotion (which is nearly every kid on the planet between the ages 4 and 24).
For example: If a little girl in her class teases her by saying "I can't believe you are wearing pigtails, are you a pig?" This girl is most likely feeling unhappy about her own looks and if you could hear her thoughts she might really be saying "Your hair looks pretty and mine doesn't. The other kids are noticing you and it makes me jealous so if I tease you, maybe they'll notice me too and I'll feel pretty.".... In this instance, if your daughter could try to hone in on the other girl's emotions of insecurity rather than her mean words, she could prevent herself from internalizing those hurtful words and helping the other girl in the process. You could role-play something like: "I know, I love my hair this way. It's out of my face and I like the way it makes my ends curl. I guess they are kind of like little curly pigs-tails. Although, does that mean that pony tails make you look like a horse? *giggles* I liked when you wore your hair like <insert honest compliment> it was really pretty. So, back to what we were talking about anyways......"
Later, away from anyone else, she can take the girl aside and say..."I know you weren't trying to be nice when you mentioned my hair today but I think it's because you were feeling <sad, angry, insecure, etc>. I like you but real friends don't say things like that."
By trying to look under the mean words, she will feel tons better about her ability to control the situation in a way that results in a happy ending for everyone.