UPDATE: If you want to transfer your account to another server, here's how to do it:
➡️ https://fedi.tips/transferring-your-mastodon-account-to-another-server
This guide is a bit longer than other guides as it includes moving your followers, follows and blocks/mutes/bookmarks.
(By the way, sorry for people seeing notification of this post edit. I had to edit as the original contents were somewhat out of date. As this post now links to my website instead, you won't get any future update notices for this post.)