Remove the monopoly on media, so much of news is simple pandering aimed at uniting one group out of rage for another. In the US, Fox and CNN are the different sides of the same coin for example. It produces better profits, so there is no motivation to bust up the monopoly of the few companies that own basically every tv channel in the states, but removing that type of rhetoric would go a long way.
Thankfully, what I’ve found is that most people are pretty normal and just care about their day to day lives and are pretty moderate/reasonable in their opinions. People who want to be assholes about politics are likely to just be assholes anyways.