Here are some hints mainly for beginners to shorten the time developing the "feel" for aiming.
There is no simple aiming technique in this game, we all know that. Imagining a ghost ball or remembering the contact point on the OB while moving along the table or looking down to your cue tip is not easy. Pros who barely miss a shot never actually think about contact points or ghost balls. It is about the "feel". In other words: the brain memorises many situations and is capable of automatically interpolate for new situations. The brain switches from calculating to look up memories and repeating. The memory of a situation is built by repeatedly experiencing it. However lots of missed shots create confusion in your brain slowing down this process. That is why you will not make a fast progress only playing. Practice systematically following my hints to speed it up.
Don't start with this until you have a straight stroke. Go through the basic lessons on stance/grip/stroke before and practice until you can aim the CB straight with no unwanted English.
Now, lets go through some geometry. Hit the OB straight it will go straight - clear. Aim a half ball aside the OB and the CB will just touch and will pass the OB with no effect on it (OK maybe the slightest throw) - clear too.
If your aim point is at the side right on the circumference of the OB viewed from your stance it is helpful to know the OB will travel 30 degrees off the aim line.
Lets make an imaginary linear grid horizontally in your view plane from your stance. The origin being the OB centre point and every tick is an eighth of the ball diameter. So you have 4 tick to the 30 degs shot and another 4 ticks to the 90 degs shot (of course at 90 degs your OB will hardly move). Here are the angles for each tick:
1 -> 7.2; 2 -> 14.5; 3 -> 22; 4 -> 30;
5 -> 38.2; 6 -> 48.6; 7 -> 61; 8 -> 90;
Make a little diagram to visualize these angles and try to memorize them visually.
(Good to know: The contact point on the OB is always the exact centre of the section between your aim point and OB midpoint viewed from the stance.)
Now set up any cut shot mark the CB OB positions so that you can repeat the shot. Judge the angle and select the number of ticks necessary from the table above. Let’s say it’s closest to 3 ticks - 22 degrees. Take your stance and aim dead center the OB. Move out the edge aim point (4 ticks) move back half the way (2 ticks) half the distance from where you are now to the edge and move there. Shoot and watch. If missed correct slightly and repeat. When you repeatedly pot the ball watch your aim two-three seconds then look at the pocket and rails nearby (a summary of the situation) before shooting. Repeat the whole thing with different situations. This will make you learn fast.