Linda,
My pcdaughter, is by nature, a flirt. I think there are just women who are born with this ...well, in men we call it charisma...but I'm not sure there is a positive word for women.
When she was a tween I spent a lot of time talking about the difference between being popular and being respected. I used movie stars and pop icons as examples. For example--Brittany Spears---popular, Mandy Moore---respected. Lindsey Lohan---popular, Jennifer Aniston--respected. I also used older adolescence that she knew. She could appreciate the difference between how people views someone who was popular and someone who was respected. Whenever she was behaving in a manner that I found over the top, I would just ask if that was a behavior that would make her poplular or respectable. She soon learned the difference. But...she is still a big flirt!!!