Mastodon is great for talking to people without pressure or expectation. There are some celebrities here.
Follow @FediTips for starter tips.
Follow @FediFollows for curated lists of whom you should follow.
Follow @lisamelton who boosts interesting and varied posts.
Do lots of searches for #hashtags.
You can follow lots of accounts/hashtags, then set "mute for home" so they don't show up on your home timeline (ie. default feed) but you can go check them whenever you're ready.