A GOOD TRIGGER AND GOOD SIGHTS HELP
To shoot well at any likely engagement distance, a good trigger pull helps. As distances get longer, good sights help a lot. Practice helps at all distances. Bringing the weapon into action quickly is most important at close range, but shots should not be hurried. Practice, practice, practice can help counter the tendency to hurry shots.
Normally, under stress most shooters tend to shoot high so when engaging at middle distances (i.e. 15 to 25 yards) aiming at the lower chest area when training may help counter pulling shots high.
I train that with the use of small caliber handguns such as .22, .32 or .380 for close-range defense, zippers should be shot with the first round aimed at the lower chest, the second at the upper chest, and the third at the head. This puts multiple rounds into an adversary quickly and if shots go high, then at least two should still impact vulnerable areas.