Send interesting Lemmy links to people you know. That's how they get interested, and check it out. You won't convince many people by extolling the benefits of the Fediverse, you just have to show them that they'll be entertained, and maybe they'll be somewhat more likely to switch if they know it won't enshittify. I'd say you should send links from instances that don't federate with some of the weirder places like Hexbear though, that's likely to turn people off until they realize how the Fediverse works.
One thing that we could use more of that draws people in is posts about relationship issues. Entertaining for almost everyone, and pretty much anyone can create them from their own experience.