Equal distribution of wealth and power, along with trying to create universal standards of communication (I.E. speaking reading and writing) would help probably.

Plus universal access to education and birth control. And ENFORCING equality by making sure there is no such thing as inherited wealth. Each new generation would have to start form the same point. I know it might seem a little extreme, but I think it’s the only way to prevent oligarchies, monarchies, and huge concentrations of power that distort society from forming.

Plus, guaranteed clean food, water, housing, and basic healthcare for all. Get rid of the reasons for conflict, and make sure those who want to start conflicts can’t ever mass enough power to start wars and we won’t have them. A lot harder to justify fighting when you personally have to do it all yourself because you can’t order others to just do it for you.