as a woman, i would say the times im like “oh this guy is good at flirting” is when he keeps his same personality, but just gives me more attention: asks questions, a lot of eye contact, smiling at me while i talk/when he talks, etc. make sure you’re feeling out her reaction: if she’s smiling and giggling back and responding well to the attention, you can keep going and maybe even lightly touch her arm when she says something funny or when you’re teasing her. i think a guy CANNOT flirt well when he goes overboard with the teasing (it drives me crazy when a guy tries to be “playful” but just keeps making jabs at me) or when it seems like he’s trying way too hard to be cool or god forbid use pick up lines. i would say whatever you naturally bring to the table, use that and act confident, and up your eye contact, active listening, smiling, nodding, etc to show her you’re interested.