A good way to discover interesting posts on here is to follow hashtags. When you do this, posts with the tags will start showing up in your timeline even from accounts you don't follow.
To follow a hashtag, just search for the hashtag and then click the "Follow" button.
This works on the web interface and most apps, but not the official Android app. Android users will need a third party app like Tusky or Fedilab or Megalodon.
Lots more info about hashtag following:
โก๏ธ https://fedi.tips/how-do-i-follow-hashtags-on-mastodon-and-the-fediverse/