There's a really good community feature on here called groups. It works like this:

1. Follow a group's account
2. You will start seeing posts on that topic
3. You can post to the group by @-ing it

It's more powerful than hashtag following, as all group posts are actively pushed to all of the group's members. No one misses anything.

Find out more about groups at https://fedi.tips/how-to-use-groups-on-the-fediverse/

If you're interested, try following one of the friendly active groups curated at https://fedi.directory/tag/fediverse-groups/