I start standing upright square to the shot, use a CTE alignment(not the whole system) to help find shot line, drop down, couple practice swings and go. Starting at CTE makes it real easy to see the proper overlap. Kind of a modified ghost ball. Very simple way to shoot.
should be something natural i feel and not labored or some kind of ritual, something that you wont even think about after long
That's big in golf too, always watch your shot/putt to completion. You learn from the bad ones more than the good ones.
The post shot analysis is huge. I must be able to analyze quickly and accurately, just in case I get another shot. Well in competition if I am not confident that I know why I missed, I am on tilt. So another habit worth building. Includes a quick and accurate self analysis.
That's a good way to make sure you stay down at least until the object ball goes into the pocket. In particular, notice which part of the pocket the ball hit. It's good to know where the center of the pocket is -- most players don't.
The more of a 'nervous type' you are, the more your PSR can act as a security blanket of sorts and calm you down. There's something calming about a familiar routine. There have been good suggestions above for what to include but you have to find what fits you. Then once you do, adhere to it completely and your PSR will help with your emotions at the table as much as with individual shot execution.