There is a big difference between shooting and hunting. Are you a shooter or a hunter?
It took me years to figure this one out, as most of the guys in my family that 'hunted' merely set up box blinds each year and played the baiting game. When I actually started
hunting (ie. go where the deer are, rather than trying to bait them to you), I finally started seeing nice bucks.
Practice, practice, practice. If you haven't practiced a particular shot (e.g. 300 yards with a rifle, 40 yards with a bow), don't take that shot for the first time on a live animal. It's unethical if you have no idea if you can make that shot.