Correct hand position in archery is a vital part of your form. An incorrect grip can cause torque on the bow causing the arrow to fling left and right. Keep a 45 degree angle grip as well as a relaxed hand to limit your impact on the shot.
"The Avengers: Hawkeye, World's Worst Archer? UPDATED" Great information about proper archery form and stance <--- Ooo yeah I see that now. Hawkeye would have some awful bruises with his arm like that.