I'm a recovering serial mansplainer. I once mansplained why feminists were right about the patriarchy to a teenage girl that was like 2 years younger than me. I also grew up arguing on Reddit very frequently.

The main thing that helps is to train yourself to first understand where someone else is coming from. In IRL conversations make sure you're hearing what the other person has to say, not just listening until they say something you disagree with then waiting until your turn to own them. Never start a conversation assuming the other person is acting in bad faith (unless there's a good reason to believe that, like they're wearing a Ben Shapiro merch shirt or whatever). Remember that natural conversation is just not capable of convincing someone that their strong beliefs are simply not true; you can either talk with them to gently steer them in a better direction that they'll have to open their minds to, or engage in discourse to appeal to an audience with a superior image which still means speaking with relevant facts and no more vitriol than is appropriate for the situation. Obviously on Hexbear we dunk on libs pretty hard but it only works because we bring a ton of information and theory to back our points up, and we're dunking on people who generally are acting antagonistic with very little substance to back up their bad faith attacks. But you need to know when it makes more sense to take a more Socratic approach of letting the person explain why they're wrong to themselves instead of getting them defensive. No one changes their mind while they're on the defense.