In many ways, Mastodon feels like rewinding the clock on social media back to the early days of Twitter and Facebook. On the consume side, that means that your home feed has no algorithm (this can be disorienting at first).
Practically, it means that you see only what you want to see and only see it linearly. You never wonder “why am I seeing this and how do I make it go away?”. Content can only enter your home feed via your followed tags or handles and the feed is linear like the early days of social media.
First, it’s important to find an instance that caters to your interests, especially if you have more niche hobbies. Once you’re set up, search for and follow hashtags related to your personal interests, and use those to find accounts you like. Use hashtags in your own posts so that people can discover you more easily, and browse users that follow you to see if they’d be interesting to follow back and expand your network out. Keep an eye on the local and federated timeline for interesting posts, which includes all posts from people on the same instance and from all federated instances. Eventually, as you build up a follow list (and especially as you follow highly active accounts) your followed accounts will start introducing you to new accounts themselves through boosting posts.
It’s more work since you’re building the network yourself instead of having it spoon-fed to you by an algorithm, but it’s overall much more rewarding, and lets you tailor your experience to your own personal preferences.
Yes! your fedi client will spit out a text file (.csv format I think) of accounts you follow, or of accounts following you and I forget how many other kinds of information (like block or mute lists, etc). You can share that with others, or if you decide to migrate to a different instance, you can use that in your new account to automate following of everyone you followed in your old account.