In order to shoot center pocket, pinpoint aiming is required. It feels nice to have an accurate shot rather then to make a sloppy pocket and on long shots an accurate aim becomes more of a necessity. Pinpoint accuracy requires a pinpoint aim, that is, when determining your object ball contact point do not have a general area. Make your object ball contact point be like a pinpoint, not like the size of a dime. If your object ball contact point is sloppy so will your end result. It also takes total concentration on that pinpoint spot to not lose it, in other words, keep your eye on the OBCP and not jump back and forth between the Cue Ball and Object Ball.
Sample aiming scenario:
Address the shot by aligning yourself looking at the angle of the cue ball, object ball and pocket while you are standing up. Get yourself in alignment as if you were the cue. This is the time to determine how you want to shoot, what type of power and cue ball control you want. Look at the object ball contact point and see the pinpoint, concentrate on it as you bend down to shoot, do not take your eyes off of the point. Take a couple of warm up strokes while still concentrating on the object ball contact point. Now you are aligned and stroking and if you do not move you should be able to make the shot with your eyes shut. This is the time to look down at your cue ball for the first time to ensure you cue is where you want it, center hit, English, draw, etc. This is just a short glance because you do not want to loose the object ball contact point. Look back up, re-orient yourself on the object ball contact point and concentrate on it while taking another couple of stokes then make your shot. While you are stroking you can see the end of the cue in your peripheral vision. You can see if it is wiggling or going dead straight. It does not require a look down at he cue and watch it go back and forth. The important part it to see the pinpoint object ball contact point, not a general area and to keep your concentration on that point. The more you look elsewhere, the cue ball, the cue, what may be standing around the table, the more you will miss your shot.
As you get used to aiming, the process will not be mechanical, your movement will flow naturally. No ghost balls, no clicks, you just see the spot and shoot. When you find yourself missing for unknown reasons, go back to the above basics and it is a good chance you will get out of the slump. What you will probably find is that your pinpoint has gotten sloppy or just lazy, it has become a general area not a pinpoint. Also you will probably find you started paying too much attention to the cue ball and lost concentration on your object ball contact point.