Pass a Constitutional Amendment acknowledging explicitly the Government's inherent DUTY to regulate its elections according to each individual citizen's equal right to speak DURING campaigns corresponding to their equal Voice/Vote at the END. Legislation can then be passed that enforces it at local, State, and Federal levels by monetary and media measures, allowing fine-tuning.
Voting should be mandatory, you should only be able to opt out by physically going to the polling facility and voting to opt out of that particular election. Voting should be done in person on paper ballots with a representative from each party stationed at each voting station. Ballots would be counted there in front of everyone before leaving the building and posted in the media. This would make it impossible to fake election results. This system works well in Australia.
One big RE-Election ASAP because of the outrageous amounts of dark money that bought the last one. Candidates will only be allowed a set number of television/radio/newspaper advertisements and a set number of mailers & street signs. They will be required to participate in multiple live aired debates. Voting machines will be prohibited; paper ballots only. Voting will be mandatory with fine imposed on those who don't. Election day will be a national holiday so everyone can make it to the polls.
A constitutional amendment to change our two party system to a parliamentary system where greater amount of the populace are represented. Instead of only the Richest people having & corporations having a voice. This would bring more people in to the activities of the Government, stronger turn out at the voting poles, and better choice as to where our monies are spent. Like less military, more Education, and Environmental concerns. Break away from fossil fuels, Green Power Grids, etc....
Public funding of election campaigns--something similar to the British system, with strictly enforced caps on private funds raised, would return government to the people. It would do an end run around Citizens United. Establish a national initiative process, similar to the initiative process that is legal in 24 states, to give the people a voice in making laws that Congress would never pass because they're not in their best interests, such as limiting Congressional benefits and pay,