Woodchuck's links are great, and I saved them for my own later reference.
Just want to be sure you're asking the right question, 8up. If you're shooting your arrows into tight groups fairly consistently, but either the groups are high right, or the occasional arrow is going high right, then you're asking the right question.
On the other hand, if your arrows are going all over the target, but after you shoot a lot of arrows, most of the holes seem to be high right, then I think your question should be: why are my arrows not grouping?
To look for reasons why an arrow might go high right before you can consistenly shoot groups is like reaching for the fine sandpaper before you're done with the drawknife when you're making a bow.
To consistently shoot groups, you first have to make sure your equipment is capable of shooting groups: Is the bow well made and are the limbs straight and not torqued? Are the arrows tuned to the bow? Is the bow the right weight such that you can hold it steady at full draw?
Secondly, you have to have to learn the fundamentals of good form, which involve holding the bow correctly, your own posture and breathing, drawing and releasing, and follow through.
Then you have to shoot enough arrows with good form until they begin to group for you. "Enough" could vary from one arrow, if you are a natural, to thousands of arrows, if you're like me.
When you can shoot 6" groups at 15-20 yards most of the time, then it's time to fine tune.
Please don't be offended, as I'm not saying you can't already do that; I just don't know if you can from looking at your target.