Can she tell if the other kids mean well, or is it teasing? It's possible that the other kids truly mean it. In that case, I'd say a smile or a "thank-you" might just do. And your daughter can also compliment others when they do well in something. I personally think it's actually a good habit to compliment people when they do well just because.
If it's teasing, perhaps talking with the teacher would be a place to start? Assuming that the teacher knows something about teaching kids to be accepting.
