Mike's one piece of advice for new Mastodon users - dive into that Federated column and follow ANYONE and EVERYONE who looks like they've posted anything at all interesting to you. Just hammer the button. There's no penalty for mistakes. Go wild.
Later, when your Home timeline is buzzing, go in and unfollow people you decide you're not enjoying so much now.
Then do that again a few times. Then some more. Forever.