A couple of weeks before the midterms I'm going to get a packet in the mail containing my ballot, instructions for filling it out, a pamphlet where every candidate on the ballot gets a paragraph or two to make their case, and a prepaid return envelope. I fill out my ballot at my leisure, stuff it in the envelope, sign the envelope underneath the flap, and drop it in a mailbox. There's a receipt with an anonymous serial number in the packet that I can go online and use to verify my ballot has been received. If I'm worried about missing the deadline there are also dropboxes in most government buildings I can drop my ballot in up through the day of the election, along with a few traditional polling places open on election day.
Voter turnout here is about twelve points above the national average.