Get rid of gerrymandered districts and go back to some version of paper ballots (at least as a safeguard against hackers). I also suggest automatic voter registration and automatic early voting ballots to be mailed to every voter. And finally, mandatory early in-person voting and election day be a national holiday.
All of these, of course, will mean that Republicans will lose so they won't happen.
Mandatory provision of sufficient resources, voting locations and staff to cater for a 100% turnout with a maximum wait time of 30 minutes. Large personal fines for the senior official in charge of any district that fails to meet this standard. Given the typical turnout is well below 100% this should completely eliminate queuing.
Paper ballots.
Electoral boundaries to be set by an independent non-partisan body, with a mandate to minimize boundary lengths within sensible geographic constraints.
Mandatory registration to vote, with small fines for non-compliance.
Mandatory attendance at a polling place, on or before election day, unless a postal vote has been arranged, again with small fines for non-compliance.
Instant Runoff Voting
Voting only for legislative assemblies and government executive positions (eg presidents, governors). Judicial and junior state positions (Judges, sheriffs, civil servants, District Attorneys, school board members, dog catchers) to be appointed based on merit, not elected. Referenda only on constitutional amendments.
The Electoral College to be expected to reject obviously unsuitable presidential candidates, regardless of state and/or nationwide voting results (or to be disbanded in favour of nationwide IRV).
Primaries to be eliminated, in favour of candidate selection by a vote of fully paid up political party members only.
Campaigns to be publicly funded, with each candidate given $100,000 to spend, which must be refunded should they fail to secure 5% of the vote. No other money to be spent on campaigning, with candidates disqualified for any breach of the $100,000 cap.
No campaigning permitted except in the two weeks prior to election day.
Automatic jail terms for any representative, senator, governor or president who accepts any gift worth in excess of $50 from any person or organization while in office. Elected office holders total income to be limited to equal to their in-office remuneration for ten years after leaving office. Any income above that level to be taxed at 100%.