Hold control is the process of keeping your sights properly aligned with each other and the target, while minimizing movement through the process of taking the shot. Simply put, it is keeping the sights on the target as you pull the trigger, until the gun has fired.
Breathing control is the process of regulating your breathing in order to minimize body movement. Breathing control IS NOT the same as holding your breath. Holding your breath can result in muscle tremors as the body starts to crave oxygen. DO NOT hold your breath while shooting! Doing so can cause sufficient oxygen deprivation, especially in high stress situations, to cause you to pass out! Use the natural pause in the breathing cycle, after you exhale, to control breathing and minimize body movement.
Trigger control is the process of pulling the trigger in a slow and continuous motion, until the hammer or striker is released, firing the gun.
Place the index finger of the firing hand on the trigger, centering the trigger on the pad between the finger tip and the first joint
Slowly squeeze the trigger, in a smooth continuous motion, until the hammer or striker is released, causing the gun to fire
The trigger break and discharge of the gun should be a surprise. This reduces the tendency of ths shooter to dip the muzzle of the gun, in an attempt to counteract the recoil, which usually results in shots impacting lower than the intended point of aim.
Follow through is simply the process of applying all funduamentals through the entire process of shooting, as the gun discharges, recoils, and the sights are brought back into alignment with the target in preparation for the next shot.