The way I do it is to follow the hashtags I'm interested in, see the people that post under it regularly and decide if they're interesting enough to follow. This has a chicken and egg downside, as these people won't appear at all if nobody on your instance follows them, which is unfortunate. :(
To circumvent that you can use mastodon social's tag page, but it's less user friendly. See here an example: https://mastodon.social/tags/activitypub