One way to have fairer, more representative elections is to give voters 1st, 2nd, 3rd, etc. choices of candidates on the ballot. If the 1st choice loses, the vote goes to the 2nd choice.
With this system, candidates favored to win have an incentive to include at least part of their politically similar competitors' agendas if they want to capture those votes.
In addition, the Nader/Gore syndrome is avoided. Voters could send a message without casting a de facto vote for the other side.