We tried to create a one stop page on our website in regards to upgrading Tableau Server.
There are definitely items that could be used as a checklist and for just about each section we have a short video that shows you how to accomplish some of the tasks if you've never done them before.
Also, any upgrade is no different than a regular install. Follow the instructions. There are no special tricks or short-cuts, only the common consistency of a regular Tableau Server install