I like to use things from all the great PUAs... but i'm naturally good at teasing/cocky funny... Here are a few examples that work like a charm:
Her: she whines, complains, or says something negative
Me: Somebody woke up in the wrong bed this morning
After you bust on her and she says your mean
Me: What you can't take a joke?
She says your too funny
Me: nah thats impossible
Her: My hair looks bad
Me: Didn't want to say anything
At mall a great opener is when she's looking at herself in the mirror. Just say: Dont worry, you don't look THAT baddd...