Paper ballots; there is no verifiable election tally without them short of forensic audit with canvassing. Voter receives a receipt of vote at polling location and can check that online against the final tally. Enforce that state legislatures - not governors, SoS, election boards, courts, nor congressional attempts to unconstitutionally federalize elections - have sole authority to conduct elections. Mail ballots should be used absentee only and should be cut-off one week before election day, meaning those votes are already processed on election day. NO ballot boxes. Voter ID should be necessary for in-person or absentee request. Partisan observers should be allowed to sit in the lap of counters if necessary to see what it being counted. Races should be called evening of election. Ballots not forming to state law are to be rejected.
Prosecute: any persons who facilitate breaking election law, whether governor, SoS, judge, etc. Audit and prosecute chain of custody violations and breaches of cyber security. Voting systems providers or representatives should never have custody of any voting data (such as thumb drives, optical media, etc). Prosecute states for not maintaining voter registries which they are bound by law to do.
I'm sure there's more, but those things spring to mind.