Another user in this thread posted a comment[1] containing a link to http://www.unmung.com/mastoview?url=mastodon.technology&view... which no doubt will come in very useful for browsing local timelines of other instances to find interesting users.

[1]: https://news.ycombinator.com/item?id=16742180

On the left there is a search box. Type in a hashtag and it will give you a list of possible hashtags. Click on one of them and the search results come up in the right-hand column.

Your instance may vary, but that works on mine, and is effective.

Either that or follow a few people and then see who they boost. Follow those boostees if they look interesting. Growth is slower and more organic, but it's a good way to keep growth under control and not end up with a firehose.

There's #ff or #followfriday for suggesting, but i've seen it used to ask for suggestions as well.

There's also Freya, the Follow Friday bot, who will randomly throw you suggestions and let yourself be added to the pool. https://botsin.space/@FollowFriday

You can search on #introductions and see a lot of people making often-hashtag-laden posts describing themselves.

Judging by the recommendations in the comments here, this would be a great place to start.