I've only harvested around 10 whitetail deer so far at 36 years old now I only had one issue that almost led to losing the harvest. The young swamp buck was 45 yards away when I first spotted him standing in a swampy area and he was looking right at me. I was stalk hunting in the woods moving very slowly on and old concealed logging trail. He was front first quartered away a little and I slowly brought up the .243 shooting 80 grain federal factory hunting rounds, and I shot him right in the brisket right into the vital area. Then he and 3 more deer that I didn't even see all took off running to the left. I knew I had to have hit it, and I looked everywhere for signs of blood and couldn't find anything. I found him over 100 yards away, and I looked all around and still couldn't find any blood. The soft point bullet penciled through the vital cavity and gelitized the organs. The exit hole a ways behind the shoulder was small. I just can't believe that deer had enough adrenaline to run that far away.
My favorite shot is behind the shoulder through the upper part of the heart and exit out the shoulder, it's a rather low shot into the vital area but it drops them instantly. But most of the time I'm just shooting for the heart visualizing right where it is within the deer.