such a simple question . . .
This is such a simple question to have dozens of answers. For me, I have looked at the cue ball last, the object ball last, a point between the balls last, a point behind the object ball last, and nowhere at all, a thousand yard stare, all with great success. The only time I really shoot like dirt is when I shoot with my eyes still moving. One thing I have noticed which may be worth considering, when I look at something close my stroke is more constricted, when I look at something further away I naturally stroke more freely.
Here is something for all of the object ball last people. Go to the pool hall and grab a cue ball and polish it up good. Set it and a single ball seven or eight feet apart on the table. Don't set up an extremely tough shot, just one that requires a little attention. Then start roping in "victims" as they pass by the table. Tell them you want them to cut the ball in the pocket on the other end of the table hitting the cue ball on the logo that can be square center or favoring english how many people shoot this shot. I found that the "A" players and Shortstops never hit the ball on the logo until after a few shots when they learned this was the object of the exercise then they changed focus and were able to do it.
Then I roped in a couple of absolute bangers. These guys aren't even regular bar room players, maybe three or four times a year players. They had to focus on the logo to try to hit it and they hit it perfectly every time regardless of where I put it!
It is hard to compare shooting pool to most of the other things mentioned because when we are trying to hit a moving target or hit a target with us in motion we most often focus on the target. A gun with iron sights or red dot is the exception, front sight is everything if some parts of the equation are in motion or all stationary. I would have to say that the tip or cue ball equates most closely to the front sight so by that comparison the cue ball would be what to look at however pool may be a rule unto itself just as shooting with iron sights is. Shooting a bow instinctively, no sight, I looked at the target but also had the arrow in my line of view so that I knew exactly the angle it started off on.
Watching video I have seen many pro's shift their vision to the cue ball at the last instant, even those that say they look at the object ball last. Those that say they look at only one thing are often looking at multiple things too. Not that they deliberately mislead but close examination of video is a far more accurate way to discover what people really do than asking them. That is why some talented competitors make horrible instructors, they are trying to teach what they think they do, not what they do.
I checked this in another sport. Out of 80 shooters over 75 said they shot "free recoil". Walking just behind the line during several relays of a major invitational shoot I found that over 70 of these shooters were not shooting free recoil! They would have been very upset had I disputed that they shot free recoil as I did tell a few after the shoot was over. Too much of a sharking move to tell them while we were in the middle of a competition.
Playing my best pool when I am putting in the most hours I just come down on the line and fire most of the time. The more I pay attention to what I am doing the more I miss. When I am struggling I carefully build each shot but there is no flow and each shot is a battle. This is when vision tricks can bite me too, which eye is dominant at the moment or true binocular vision. I swap between all three and not recognizing which I am using at the moment can result in spectacularly bad misses!
Hu