Think you might want to save on paper and give out your email address when you register to vote? Dear god. San Francisco doesn't give voters the ability to only receive correspondence from the Department of Elections. The spam is insane. Obviously you get all sorts crackpots running for office that'll spam you endlessly. For a while I was even getting email about pet clothing from some guy. Turns out he ran a failed mayoral campaign and then turned around and used the voter rolls to promote his business (because clearly I want a tutu for my non-existent dog).
And, sure, you can remove your email address from the voter rolls but not your physical address (so that spam will continue unmitigated). San Francisco is an extra level of special here as it doesn't even bother with HTTPS for their Department of Elections stuff.
My main actual trick has been to be discerning in the things I sign up for and never filling in information that's not required.