While the likelihood of needing to make a long-distance shot with your pistol may be low, the risks are undoubtedly high. However, aside from its tactical importance, improving your ability to accurately fire your pistol at longer distances will make you a better shooter at more likely engagement ranges.
Being able to hit a target at a distance will always make hitting a closer target much easier. Yet, there are some nuances specific to shooting with a pistol at longer ranges.
When it comes to shooting, the more balanced you are, the more accurate you will be. Therefore, when a long-distance pistol shot is required, getting into a low kneeling or even prone position can be advantageous.
When making a long-distance shot, whether supported or unsupported, you may need to account for the time it takes for the bullet to drop from the barrel. This may be one of the few times where a loose grip is advantageous, as it allows the barrel to rise more during recoil, putting the bullet on a higher trajectory. This helps compensate for significant bullet drop due to gravity and drag.
As the distance increases and the bullet becomes heavier, bullet drop will become a more significant factor. Therefore, consider the height and aim high. How high it is will be everyone's own estimation, so you need to practice regularly.
Trigger control is an essential skill regardless of the distance, but when your target is hundreds of meters away instead of 10 meters, even the slightest mistake can cause you to completely miss. Nowhere is pressing a soft and sensitive trigger more critical than when shooting with a pistol at long distances.
Ideally, you want the shot to be taken during your natural respiratory pause, i.e., after you exhale and before you inhale. Your body is the most motionless at this point. However, if you wait too long, you are likely to do more harm than good; start over when you feel your body is screaming to take a breath.
While the likelihood of having to make a long-distance shot to defend yourself or someone else may be low, it is not zero, so you should add long-range shooting to your firearm training. The most significant benefit of this is that it will also make you more accurate at closer distances.