How can we make sure voters do not vote more than once in a single election? Probably the best way to do that is to tie each voter to some ID number, like a SSAN, which would set off alarms if the number was used more than once in an election.
How can we make sure voting machines are not corrupted to flip votes or create fake ballots? Probably the best way to ensure machines are not corrupted is to require every machine to take photos of ballots when the voter votes as well as show the image to the voter to ensure the ballot is marked as intended. Those stored images could then be reviewed by a bi-partisan panel of election officials for verification immediately after the election before anyone else is given access to the machines.
The voting machines could also have a log of every transaction recorded to be reviewed by a non-partisan IT expert for verification that the machine had not been tampered with.
How can we make sure absentee ballots or mail-in ballots are not used to create false votes? We could stop sending out ballots to every voter on the roll whether the voter requests one or not. We could purge the voter rolls of the names of ineligible voters before the election. We could require absentee voters to use their voting ID number on their ballot to ensure ballots are not being filled out for ineligible voters.
How can we make sure election workers do not destroy ballots, edit ballots, or miscount ballots? We can require election precincts with a history of fraud complaints to be required to have live cameras focused on workers as the handle ballots.
How can we stop illegals from voting? We could require every voter to produce verification of citizenship and that could be done when issuing voter IDs.
There are no doubt other measures that could safeguard our elections, so crooks do not disenfranchise legitimate voters with fake ballots.