I think there is, and that is just do stuff! Upvote, comment, engage, submit posts. Obviously helping confused individuals directly if you see them also helps, but simply using the service and engaging with it will ensure that more people join, and stick around when they see something worth returning for.

Most of the tech users that ditched Twitter for Mastadon when 3rd party apps were killed actually stayed, and still engage with that service. The other communities I followed on Twitter didn’t, and that’s because they joined a ghost town when it came to their interests. Lemmy is far behind where Mastadon was then in terms of overall capability and client options, so this is a big hurdle to overcome. Everyone has a part to play :)