Quick newbies' Mastodon guide:

1 Read the rules before joining a server 2 Write an introduction post & pin it 3 Use hashtags a lot! Mastodon isn't searchable without them 4 Content Warnings (CW) are used on Mastodon much more than Twitter. If in doubt, use the CW button 5 Use the CW button for political posts! Add #politics, #USPol, etc. in title 6 Use https://fedifinder.glitch.me to export your Twitter followers who have Mastodon accounts linked 7 Watch out for romance scammers 8 Have fun!