For me, I think too provocative is when your ta-ta's are almost out of the shirt. Also if your skirt is so short that when you sit down we see your underwear (or lack of)....same goes for jeans too! The first thing I notice about a woman is her smile. I get a visual of what pictures would be like if we took them together.
I have categories as well and they go like this:
1. strictly a friend (who lets me know how to decipher a woman's language)
2. the "meet my family" girl
3. "wouldn't let you meet the family" girl
4. "she might be nasty" girl