I've spent some time, looking for examples of negs. I don't know mean the how, when and why we use them, that's covered in posts that are easily located. I am having trouble finding them in one place or the posts may be a little old. I would be grateful if anyone can give me field tested examples of negs, that i could adopt.

offering her a piece of gum after she speaks but not taking one for yourself

asking a girl what her natural hair color is

asking her about her mannerisms for example "why do you keep blinking so much?"

havent field tested this yet but ill let you know how it goes: making fun of another person in the area for something that she has too.
for example if the target has a ponytail, saying "look at how goofy that ponytail makes that girl look"

overall anything that will make her self-conscious is good but you dont wanna come off as an ass so your tone has to be pleasant and innocent and sometimes a smile is good too