They don’t show the “secret” technique on those wikipedia photos. But for those that want to go back to a sort of Wildfire type Hunger Games setting, that’s what you should be aiming for.
Smaller bows are better, using modern construction. Leave the long range stuff for the .50 caliber sniper rifle users.
General human mastery needs around 10,000 man hours of practice. A repost of something I got from http://benotdefeatedbytherain.blogspot.com/
Highest mastery feat for handguns is to be able to shoot from the hip or from non conventional angles, and hit a target at about the same range accuracy point as regular people using two hand stances on stationary targets. Same concept. Cross wind calculation with 2 km sniping targets, same concept. Same concept, different applications though.