...of their own tricks.
Conservative activists like Richard Viguerie pioneered direct mailing for political fund-raising and action in the 1970s, using early forms of data mining to identify which people would respond to which hot-button issues. Punching their hot buttons made them more likely to cough up some cash and to single-issue vote, which helped find ways to break up the Democratic Party's New Deal coalition.
Going back farther and continuing into the 90s or later were political newsletters (such as Ron Paul's) where conservatives could get "the real deal ignored by the liberal media."
Also far back and continuing thru today is conservative radio. Rush may have been given free reign by Reagan's ending the fairness doctrine, but before him people like Bob Grant got a widespread audience (including far outside his broadcast area). And you can't leave out shortwave stations and, even more, the hundreds of AM stations across the country owned by religious broadcasters. They had a lot of leeway in what they covered as long as it had a religious hook, and they blanketed much of the country long before companies like Clear Channel could buy up stations to get similar geographical coverage.
These all gave their readers/listeners a sense that they were getting the straight dope, from people brave enough to come out and say it, not just conform like "the sheeple." They, and their favored sources, were the ones who were right.
Moving into the late 80s and 90s, add USENET groups, dial-up BBSs, and early online forums. My recollection is that these skewed strongly to conservative or libertarian views until the late 90s, when liberal forums started catching up. This is also when RWers started their habit of aggressively taking over any political talk on nonpartisan forums, not through compelling argument but through the now-familiar habit of disregarding sources outside their own favored places, dismissing it as "liberal propaganda." Other people got tired of arguing with a brick wall and, being less obsessive about it, stopped bothering. And there was belligerent trolling, of course.
Let's also not leave out e-mail forwarding networks, through which they could circulate articles and posts without having any pushback. Quite a few of those were also frauds (e.g., taking the transcript of Sen Al Gore questioning Ollie North, North talking about Abu Nidal, and the circulated transcript edited to replace Abu Nidal with Osama bin Laden in order to make it look like North warned about Bin Laden years in advance but "stupid, traitorous Democrats" ignored the threat).
There's a reason why Russian bots are indistinguishable from RW foamers. It's what they were patterned after. Why re-invent the wheel when it's already there. Just install a second set of controls.
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