I don’t. I browse /all and block stuff I don’t want to see. Grifters, people who post dick pics outside of gay or penis communities, and other stuff I don’t want to see. I don’t block NSFW but I leave it blurry. Most of the time I don’t want to see it (Demi/Ace) but sometimes I do.

By default, lemmy shows you whatever’s posted in any community yours is federated with, with a slight bias for posts that get upvotes.
Everything else is up to you. Personally, I like sorting by new comments instead.

How do you format your feed to make sure you’re seeing what the other side is actually thinking?

What’s “the other side”? You’re on a predominantly leftist and nerdy platform, and even here we argue all day long.
If you want to see more conservative, pro-religious or right-wing content and try your hand at arguing with morons, this isn’t the best place. And in those conservative spaces, you’ll likely be banned as soon as you disagree.

On Lemmy you’re your own algorithm. I assume you already know what you’re thinking.

Algorithms where?

There’s not one algorithm to rule them all … yet, but the platform and your interactions with it amplify over time, mainly in an attempt at creating “engagement”, ie. more opportunities to sell you shit, achieved by creating outrage and clicks.