For Diaspora and Mastodon, try to talk about other things besides your work, and keep tabs on the local lingo. Much of these users are fleeing Facebook and Twitter because they're tired of censorship, so posting writing tips and stuff isn't going to get you fans.
Drawbacks to consider: Diaspora and Mastodon, while both Libertarian in concept, tend to be opposites of each other. GNU Social is a bit more balanced. Diaspora lends more toward the political right, though occasionally Far Left like myself. Mastodon is the opposite.
And not addressing issues with surveillance and privacy issues, and trashing people that talk politics isn't going to win you any fans over there either.