I would change the single-district voting system to proportional representation. What ever percentage of the vote a party gets, that is the percentage of seats they get. This gets more people involved in voting and gives third parties more of a voice. Voting for a third party would not feel like a wasted vote. It would be very difficult for any party to receive 50% of the seats, so they would have to form coalitions with smaller parties to get their agendas through. This is similar to most European countries.