There's a lot of different aiming systems for different applications. I'm no expert nor am I a very advanced pool player. I do however like to learn and am open to new perspectives always.
A couple things I'd recommend looking into and find very useful are practice drills.
1. Bank shots, get comfortable banking balls learn how to avoid double kisses, know when you need speed to cut the angle short or English to throw the ball further.
2. There's a system called the spot on the wall system. It's essentially a mathematical equation where you shoot from the corner pocket to the 2nd diamond below the corner pocket furthest away from that corner pocket or diamond three if you count that corner pocket. This will bring you to the fifth diamond on the 2nd rail of the shot which will bring you to the corner pocket across from the corner you shot from (short way across). This is only with the application of following English. You adjust the first contact point until you're making the ball in the corner pocket as every table plays a bit different under different environmental conditions.
Once you've found the first contact point, you image that contact point extents forever, until you hit a wall (assuming you play indoors, lol) hopefully there's a spot on wall or an object you can use as a landmark for this shot. Now anywhere you can aim at that object with following English will aim true for that corner pocket so long as there's of course nothing in the way. This system is even still more useful.
1. you can use this for all 4 corner pockets
2. you can use this for aiming at the 2nd rail
3. you can adjust this system for aiming in front of the pocket if you were to shift all the angles in either direction
4. you can hit balls away from the rail by estimating the trajectory of the cue ball, this is particularly useful for hitting balls that you normally would have difficulty kicking at
3. also check out Buddy hall's clock system for cue ball control
4. PRACTICE PRACTICE PRACTICE! as far as actually aiming at the ball everyone sights differently, some people shoot with their chin right on the cue ball with each eye naturally spaced to each side, some people shoot standing nearly up right (Minosota fats), some people have their head to one side.