Read the head line and give me your opinion.

I thing the best way to get a knock out is to hit the side of the jaw.

Try to hit the area of the lower jawline and the base of the neck.
A direct hit to these areas will almost certainly drop the fighter.

When a person gets knocked unconscious by a punch it is not the immediate force of the impact which does this, but rather the force of the brain being rattled against the inside of the skull.

This means that a punch which causes the head to jerk and move rapidly will be much more likely to knock someone out than a punch which causes less movement of the head, even if it is not as hard. It also means that speed is paramount. A very fast strike with just enough power to move the head will be more likely to knock someone out than a slower punch which has more power and weight behind it.