Let's do a linux server preparation checklist, shall we?

Question

linux

There are some things that you have to do (almost) all the time. Because of their routine, many of them are often forgotten.
Let's make a checklist so that you can go through it and be sure that you haven't forgotten anything.
I understand that everyone will have their own, but for sure from the many options, everyone will be able to collect something for themselves.
I start:

• Time zone setting
  
• Hostname setup
  
• Disabling root
  

Answer 1

General
SSH (article)
SSL (article)
PostgreSQL (article)

Write backup scripts.