In red dead redemption while dueling someone how do you shoot them

Before you see the "Draw" sign and enter Dead Eye, move the right analog stick down. Look at your right hand when you do this; notice how your hand moves closer to your gun. This will greatly improve your chances of winning.
When you see the "Draw" text appear, move your right analog stick up (this may be down, depending if you have y-axis inverted). Press RT/R2 when the cursor turns white. Do that several times and you will demolish your opponent. To disarm your opponent and gain positive honor points, shoot his hand.

Skill tip: The later you draw, the more accurate you are, but the less you fire vise versa.