Join a third, fourth, or fifth party. Better yet, run yourself as an independent demanding radical liberty, equality, and justice for all. Demand non-partisan election overseers. Neither Republicans nor Democrats should be in charge of confirming election results, or controlling recounts, especially in close elections. New, standardized voting machines would be nice, too.
Democracy is in the details.
Take to the streets. To force change, you have to be visible right there where you live. You can be as whimsical or confrontational as you want, as long as you are heard and seen. Do direct action in your neighborhood. If there aren't any near you, you can do the organizing yourself.