I would start by reading about the techniques used by one of the greatest archers in the world:
Hunting With the Bow and Arrow, by Saxton Pope. It’s free at Project Gutenburg.
http://www.gutenberg.org/dirs/etext05/8hbow10.txt
This not only describes in detail the techniques of Ishi, the last Yahi Indian, but it also tells a bit of his story after he was captured and given refuge and living quarters in the Anthropology Department at the University of California, San Francisco in 1911 where he met proffessor Saxton Pope..
http://en.wikipedia.org/wiki/Ishi
Chapter 8 covers shooting technique. The book also describes how Ishi made his own bows and arrows, the wood and obsidian he used, how and where he chose the materials, and his incredible scores in target shooting while using these.
From Wikipedia:
“Today, an annual archery tournament called the ‘Ishi Tournament’ is held in the Yuba-Sutter community, about 40 minutes from Oroville, California. The tournament is open to both youth and adults, testing their skills in comparison to Ishi’s archery skills. Two awards can be earned during the tournament:
The Ishi Certificate is awarded to any archer who can hit all 30 arrows to a 20 yard target, get a score of at least 99 to a 40 yard target, and have one arrow reach 100 yards.
The American Ishi Degree is awarded to any archer who can match Ishi’s 1914 archery scores or better. This award only goes to an average of 1–3 people a year, due to its complexity.”