I think something to focus on would be a clean and easy-to-understand explanation of Lemmy and how the instances federate together.
This is still something Mastodon is struggling with when it comes to onboarding. Even for the technologically minded, it can be a steep curve and there are potentially a lot of other people who will balk at the walls of text and technical jargon.
Obviously, it all can't be fixed overnight, but I feel a lot can be done to improve the onboarding for users without overloading them with information.
Maybe a small step-by-step wizard-style system to help someone find and instance and explain Lemmy in bite-sized chunks of info would be a good first step.
Professionally I'm a UX Designer and Business Design consultant and I'd love to be able to lend expertise to the project!