The correct handgun sight alignment factor, as with others, is different for different guns and various shooters’ tendencies. Many gun owner’s manuals include the best way to align sights for that gun.
Some suggest aligning the sights right on the target (centered). Others suggest aligning the sights at the “six o clock” position which is lining up the rear and front sights and placing them just on the bottom of the acquired target.
That will be for the sights that come on that handgun. Of course, changing the sights on the gun may change the best way to align the sights. The only way to work out what works best for you is to practice shooting the gun.
This is a good place to say that the best tactical sights I have found, that will work on virtually any semi auto they are made for, are (Tritium Fiber Optic) TruGlo TFO Night Sights. They shine like emeralds in daylight, and like green flashlights at night.
Correct handgun sight alignment has to be worked out with any individual gun. But the way to align and view the sights and target is something that has to be done on every gun for correct target acquisition and accurate shooting. The way to align and view the sights is to line the top of the front sight up with the top of the rear sight.
Then, (and this is challenging when you are a new shooter) focus only on the front sight with your eyes while keeping the sight on the target.
This goes against everything in your mind and reflexes that tells you to focus on the target. But focus only on the front sight.
This means that the front sight will come sharply into focus, with the rear sight and even the target blurring to the vision. Keep your eye(s) on the front sight throughout each shot and try not to look at the target between each shot (again very challenging).
For help in mastering this, try to use some reactive targets sometimes when practicing. Reactive targets are anything that splatter, burst, break, make noise or fall over. Practicing with these type targets gives you the visual while keeping your eyes focused on the front sight moving it from target to target.
One eye or two?: In general, life shooting a gun is easier if you can acquire your target and shoot effectively keeping both eyes open. It is quicker to acquire the target and if moving while shooting it will improve your timing and balance.
However, many people, because of vision variables, are simply unable to focus with both eyes open. They may experience blurring of both sights or double vision when trying to focus on the front sight.
If that turns out to be the case with you, close the non dominant eye and shoot away. Most instructors will teach you to shoot a handgun with both eyes open. Military combat types will tell you in combat, it’s dangerous to close one eye.
But you have to remember that it’s also dangerous to point a gun at something you’re seeing two of. If you need to, close one eye to shoot. It is not going to make an earth shattering difference in your safety level if you have to use the handgun in self defense.
The most important thing is to hit what you are shooting at and not hit an innocent bystander.
Have you been delaying carrying your handgun trying to figure it all out? There's no reason to wait another day to take decisive action.