If you want to help spread the word about the Fediverse, try politely asking your favourite sites, organisations or projects what their Fediverse/Mastodon/PixelFed etc address is.
Obviously not everyone has the time or the spoons to maintain social media accounts, but just casually asking for an address will indirectly let them know the Fediverse exists.
The more people that ask them, the more likely they are to find out more about the Fediverse and join 👍