Reject the First-Past-the-Post Voting System.

Currently, for the election of many policy-making positions, each qualified voter gets only one vote. This is called the "first-past-the-post" system. Among other problems, the biggest one seems to be the fact that politics degrade into choosing one of two parties. For example, in the last presidential election, it was Romney vs. Obama, with the other candidates all but ignored.
People shouldn't have to invest in the candidate most likely to win, just to prevent their least favorite candidates from being elected.
There are alternative systems, that would allow more than just two parties to be considered. A possible solution is the "instant-runoff" voting system, where candidates on a ballot can be ranked from best to worst, so the candidate most preferred is elected.