Is there any checklist to configure before upgrade for better deciding?
Is there any checklist for it after upgrade?
I have used the Upgrade status module on the past to better understand how much work will be involved in upgrading a site from a mayor version to the next.
Also, depending on how many modifications, or modules you have, it will also make the process easier.
One more tip: Check the Drupal documentation, and remember Youtube is your friend.