Lol 60 is low? Anyways, I pick the flirt option like 90% of the times when I'm talking to her, sometimes joke and sometimes intellect. I'll admit I don't really read through most of the dialogue and I just go with the notion that flirting is the most surefire way to get the most amount of lewd scenes. What should I do instead? I'm sorry if this is all too much but you'd be helping me and alot of other people in the future that see this post from unecessary headaches.
You're good, if I wasn't so fuckin tired I'd send the save right now (I will try to later).
The best way to get Affection in this game is to almost ALWAYS (when given the option) to go with the Speech Dialogue Options (Flirt, Int, Joke).
It doesn't really matter if you Flirt and I've actually found that whichever option has the higher Level be it Joke Lvl 3 vs Flirt Lvl 1 or 2, the higher option will ALWAYS grant more Affection.
Affection is what determines whether or not you get a scene basically with a few exceptions of Routes (i.e knocking Taylor out vs Helping Her). So don't feel pressured to pick ONLY Flirt, you'll almost always be hit with a crossroads at the Affection threshold to pick "End Path" or "Harem" or "Romance".
Do note however that KISSING is the exception to this rule, and will almost always force you into a pick between "Harem" or "Romance" with NO "End Path", option if your Affection is a certain level that is.
Edit: My Affection by the end of the Party with Nikki was basically 103 or something along those lines. I missed her ass EVERY chance I could.