Use a Password Manager
The best tip we can give you to keep your accounts safe is to use different passwords for different platforms. That way, even if someone logs in to one of the platforms you use, they won’t be able to access others.
With that said it can be tricky to remember all your passwords, which is why a password manager is really important.
Using a password manager like Apple’s built-in password manager or Sticky Password will guarantee that your passwords are safe no matter which device you use. Not only that, but it’s way more secure than saving your passwords in a note that supposedly only you can access.