From a newcomer to a newcomer, here's what I've discovered and found useful:

1) If you can't find the answer, ask people. Post the question and add a hashtag. Also, follow the @FediTips account.
2) Notifications get sent to your email. You can disable that in settings.
3) Your feed is chronological. It shows posts from people (and hashtags!) that you follow.

I'll continue in the replies.

#Fediverse #NewbieToNewbie #tips #howto #Mastodon #newhere

4) Your feed contains posts that your contacts boosted (reposted). If it looks overwhelming, you can switch off boosts from everybody or only from some of the accounts.
5) If your feed updates too often too fast, you can turn on the Slow Mode in your settings.
6) You can filter out posts based on the words they mention, by adding the word to your filters.
7) Most instances, including mastodon.social, have a post limit of 500 characters. There are instances that have 5000.
8) You can move to another instance, taking your followers with you. You can also download all your posts, but you can't upload them onto your new instance.
9) There are many apps for Mastodon. I prefer not the official one but Ice Cubes, although I mainly just use the website version.
10) To send someone a private message, tag them, then choose "private mention" in the top left corner of the message window.