How does dueling work in Red Dead Redemption?
I had trouble with dueling too. Perhaps try shooting where your crosshair lights up red. Also wait until dead-eye automatically engages and it tells you to draw. (?)
You can also try disarming the guy by shooting him in the hand. Some people, usually story related, cannot be disarmed, as such aiming for the hand will only get you killed instead, which can be frustrating.
Rockstar discussed it a little here, hopefully this is helpful: http://www.rockstargames.com/newswire/article/5991/rockstar_game_tips_dueling_like_a_pro_in_red_dead_redemption.article
As an addendum to Teebery's 4 points:
5.. Every trigger pull increases your duel meter, which needs to be higher than the other guy's to win.
6.. You get more duel meter off some parts of the body than others -- like head or gun hand. You also get more from a white crosshair than red.
7.. Shooting the opponent's gun hand will often instantly end the fight. The opponent will remain alive, be disarmed, and you'll get significantly more Fame points.
- Don't pull your gun until the "draw" command.
- Put the cross hair on a fatal part of the body (chest is easiest).
- Wait until the cross hair turns white and then fire.
- Repeat until he dies.