Peer discovery and peer suggestions are not implemented yet. People have been posting their public keys on twitter etc. There is a proposal for encoding a set of followers/followed in a message which your followers' clients can then use to display info about that on your profile. That should help with peer discovery once someone codes it up. You can also find threads that people are widely commenting on (e.g. someone might post a nostr thread on twitter) and follow people who post in those threads.