The guys have covered most things that can cause shooting to the right. One thing has yet to be mentioned though. Are you sure your anchor puts the arrow directly under your eye and not to the left of it?

Stand in front of a good sized mirror, draw your bow and aim at your eye in the reflection. Is the point of the arrow aimed at your eye or off to the right? If you're not looking directly down the arrow at your eye, then let down and move your anchor to the right and try again. Keep doing that until you find the magic spot where everything lines up.