Make voting not just a civil right but a mandatory one. A government of the people, by the people and for the people requires the participation of the people.
Why is this important?
On average around 60% of the people who can vote actually exercise this right. That means on average, Presidents and senator's are elected with just over 30% of the voting populace. The majority of the people who vote are polarized to one party or another and the majority of the people who are in the middle don't bother. In order for Democracy to truly work requires the participation of the people as a whole.