Put It On Paper!
Paper tuning a bow involves setting up a piece of paper on a frame, stretching the paper taut, and shooting field-tipped arrows through it from about 6 feet away.
The paper should be set high enough so it's center is even with the height of the arrow as it is fired from the bow, using good shooting form. A good backstop is placed 4 or 5 feet behind the paper so the arrow passes completely through the paper before it hits the backstop.
This will assure that the tears in the paper caused by the arrow will not be affected by how the arrow moves when it hits the backstop.
As the arrow passes through the paper, the point will pass through the paper first, followed by the shaft, followed by the fletching. The tears are then examined to determine how the arrow is flying. The point of the field tip will make a small round hole in the paper and the fletching will make a "Y" shaped hole. The location of each hole, relative to each other, will tell you how the arrow is flying.
If an arrow is coming off the bow perfectly horizontal, the point-hole will be in the center of the "Y". This is the way you want your arrows to be flying.
General Corrections When Paper Tuning a Bow
Tail-Low tear indicates a low nocking point which can be easily corrected by raising you nocking point a 1/16" at a time.
Tail-High tear indicates a high nocking point. Lower the nocking point a 1/16" at a time until the arrow point and fletching appear to enter the same hole. Once corrected, you arrows will stop porpoising.
Tail-Left tear usually indicates a weak arrow for right-handed shooters while left-handed shooters will experience the opposite pattern. You can either decrease your bow weight, use a lighter broadhead, switch to a stiffer shaft or increase the plunger button tension. Release shooters may have to move the arrow rest slightly to the left.
Tail-Right tear usually indicates an arrow that is too stiff. The opposite pattern will be seen by left-handed shooters. You can either increase the bow weight, choose a weaker arrow, decrease the tension on the plunger button, or use a heavier broadhead. Release shooters may have to move the arrow rest slightly to the right.