Read the hints, you're probably missing some requirements. If it's love points, take the girls to the pool/beach.
Right now I'm focusing on Ai, since I've neglected her progression, but other than that, so far I've progressed as far as I can. Hibiki's progression so far the only roadblock preventing me from going any further. I've got her at 23/25 while the other girls are past their mark, so I'm stuck on her progression her until the card game triggers.
