Tuning a bow properly is going to be different for each individual bow. The first thing you have to do is to pick the right arrow with the correct spine stiffness for the draw length, draw weight, and broadhead weight. If you have a compound bow that has a solo-cam, tuning the bow can be shortened by at least 350 curse words, not saying 2 cam bows cannot be tuned, but require tuning regularly as strings stretch, etc. Next, arrow rest selection cannot be left out. If you use a whisker biscuit, a perfect hole through paper will give you the best results. A drop away rest can be tuned with a perfect to slight tail-high tear for best results. Drop away rests are the new rave, but you are also adding another moving part that has to perform flawlessly each and every shot. Launcher style rests will usually perform best with a slight tail-high setting. As long as you have an arrow with the correct spine, and have good enough form for repeatability, adjusting for tail left for right should be corrected easily by adjusting the rest to the left or right. Usually this spot will be slightly to the left of true center of the string.
Arrows on the other-hand are like factory loads. Some of them don't shoot worth crap. Solid carbon arrows have the advantage of not bending and being lighter than aluminum. However they are not as straight and spine strength is not as consistent. If money is no object, the best of both worlds is the Easton ACC arrows.
Having a bow prefectly in tune will not always produce the tightest groups down range. Adjusting the tail-tear slightly may improve consistency down range and improve your confidence level too boot.
Hope somebody found this helpfull.
"The most terrifying sound in nature is not the roar of a charging lion, nor the whistle of a descending bomb; rather it is a click when you expect a bang." - Peter Capstick