I believe that spacial awareness has a large part in aiming. What your eyes see isn't everything, though that's huge. Some shots are rife with optical illusions/distortions. Knowing how to deal with that and trust what you're seeing is crucial, and sometimes this takes an awful lot of table time. Some shots require techniques to minimize such illusions, especially when they look weird. You know those shots that look odd so you adjust at the table (bad habit) then end up missing by the amount you adjusted? Those.
At some point the visual data morphs into spacial awareness. Add in touch or feel and shots becomes the ones you can't miss. The ones you cant miss are more frequent when your fundamentals allow you to come down on line with the shot. Basically when you transition into the shot it's already a given. You can look at OB last, CB last, the pocket, a fly on the wall, a ghost table, or even close your eyes and the shot goes. If one thing is off though you may miss, especially if you're still refining your fundamentals.
It takes time to learn how to aim different shots. There can be a lot of visual trickery involved and I think we all see shots differently and somewhat use different methods to make them.
I'm probably not explaining this as well as it could be explained but it's tough to put into words. At some point your subconscious has enough data and training to make the shot. Sometimes you have to be very mechanical until you learn certain shots. Once you learn them though I feel that you should just let the shots happen rather than try to dominate it through calculations and such. At some point I think it's conducive to let the subconscious do the work and not second guess it. When shooting you will do best with a clear head and not in calculation mode.