This country has been controlled by two major parties in large part because of the way we vote. An instant-runoff election would not only be more democratic, it would also encourage people to vote for their favorite candidates regardless of their party without the fear of their least favorite candidate winning.
Here are two great resources explaining how this process works and why its superior to how we currently run our voting system.
https://en.wikipedia.org/wiki/Instant-runoff_voting
https://www.youtube.com/watch?v=3Y3jE3B8HsE
This would help represent more people and more ideas. It would be better for the people of our country.
It would promote more transparency and accountability from our politicians.
Overall this process would be a huge step in the evolution of our processes.