Issue student season tickets to any interested students for free. Charge an unused ticket fee for any that are wasted.
What if they're busy and cant attend or say an emergency comes up? These ideas are futile. There will always be a student section. They are the live blood of the school. I graduated last year, if i recall for those who didn't own season tickets, if they didn't scan their code they lost priority in obtaining future games. Even with this practice in place, people walked in, scanned and turned around to the bars or to tailgate. We wont see something change until the team is good. There is always a nice turn out for a big name opponent.