Shoot the basketball.
The actual center of mass on most human beings is right around hip level. That is simple physics.
The place I have been taught to shoot game animals is "in the basketball". This alludes to the thoracic cavity wherein the lungs, heart, and other organs are located, which, if hit, will bleed profusely and leave a good blood trail to follow and probably result in a swift and relatively humane death. Even if the first shot is not a one-shot kill, shoulder bones or foreleg bones, are sometimes broken, or spine disrupted, resulting in a slow-moving animal or a paralyzed one, for a safe and humane kill shot (or, in the case of a human, cessation of hostilities, medical attention, apprehension and prosecution). The "basketball" refers to the fact that in most deer-sized animals that mass of crucial organs is about the size and shape of a basketball. Shoot for the center of the basketball, and even of you are a bit off, you still hit something worth hitting.
If you are facing a human front-on, that "basketball" (more like a flattened soccer ball or oblate spheroid with the short axis pointed straight ahead) is where most of us have been discussing, pretty much right through the sternum, but if you are shooting at a person who is presenting his side to you, or from a low or high angle, you are well advised to picture that interior 3 dimensional mass and shoot for the center of that, not a two-dimensional target superimposed on your opponent.
Does picturing a 3-dimensional target help anyone focus better?