My basic pre-shot routine goes like this:
Find the landing area and the easiest and safest path to get there. If rails are need for shape, I'll mentally pick out where the cueball needs to hit on the rail(s).
Chalk up and visualize the whole shot, decide what kind of spin and stroke are needed.
Set feet and do a couple air stroke to loosen up and get the speed of the shot.
Fold into the shot with eyes fixed on the object ball contact point.
Take practice strokes while visualizing the contact between the object ball and cue ball.
Set, pause and finish staying down through the shot.
It's a lot to go through but it's mostly automatic for me know, so I don't think about unless I start struggling and need to diagnose my game.
I think a preshot checklist is something that you build into your game during practice and go back to check on when things aren't going right. If you had to go through a mental checklist on every shot, pool would be a huge chore for both you and your opponent.