Driver: pick a dimple. 3w-irons: leading edge of ball. Putter: Alignmnet line on top of putter.

On drives, I place the ball so i can view the number of my Titleist as the place I want to strike. I also use this as an alignment aid to square up the face of the club parallel to the Titleist script. On approach shots, I look at where the ball and grass meet. This allows me to focus on strking down and through the ball. For putts, again, I us the Titleist script as my alignment aid and focus on the "L" which is the middle of the ball.

Since I've been playing like crap I don't think I'm look at the ball period! LoL I look at a dimple on the back of the ball depending how I'm hitting shots that day it could be left of center or right of center. This is my impact point as to where I want to contact the ball.

I pick a dimple on the back of the ball, centred for a straight shot, closer to me for a draw and further away for a fade.
For putting in like Spieth, pick the spot the ball is gonna break from and look at it and try to feel the ball moving towards it

I don’t know that I have ever really thought about it. Usually have a swing thought in mind, maybe picture the shot how trying to hit.

I look at the number on the golf ball. It's a smaller focal point and it's an easy way to keep your head still.

Me, old school when it comes to the putter. I still plumb bob, then line the head of my putter on my intended target line.
Pick out an intermittent target between my ball and the green, line my club head on that target line. Try to avoid thinking, just executing. Bad juju.....