The main challenge is figuring out where students wish to register, at home or at college. Out-of-state students have an even greater challenge because they have moved across state lines.
To increase voter turnout in the United States, I would suggest these options: move to all-mail voting, hold elections on weekends, automatically register voters, and pass federal law that further reduces impediments to voter registration.
I would ask them their age, educational level, interest in politics, income level, and whether they voted in the last election.
Candidates with extreme viewpoints gain media attention, and primary voters are more ideologically motivated than voters in other elections.
Closed primaries do not allow voters affiliated with other parties to vote, thus keeping the decision inside the party.
Voters tend to vote for candidates who look attractive and competent. They may consider race, gender, height, weight, and other physical attributes.
People of means can easily form interest groups to propose initiatives/recalls and that have the resources to pay for signature collection.