You probably just need to advance someone else's story line to a certain point. That's why Runey was asking about character levels, he can't tell you which character to work on until he has some specific numbers, just type out the stuff in the leftmost column. If there is a *TALK* option when you knock on Maria's (or any girl's) door, it will usually tell you what you're missing (e.g. "I need to improve my relationship with Android").