I recently replaced my old arrow rest with a new mechanical one. along with that i added a quiver. Before my upgrades my old bear was shooting dead on, but now im kind of sceptical of the "first shot". what can i do to make sure my bow isnt going to kill my nieghbor and cost me another $50 for replacement arrows.

Eye ball your rest, with an arrownocked. Hold your bow with one hand arm outstretched, look to insure the string is also in the middle of your limbs, and your rest should be in the center of your string,the arrow should be point straight out, not cocked to right or left.that will get you close... If you don't want to kill your neighbor, get real, real close to your target maybe three feet away. you can look down the arrow shaft to insure your not going to miss... Good luck, if some kid comes asking you have you lost an arrow, just say, "No not mine."

I'll assume you are talking about a drop away rest and are using a release. I also assume the drop away has a "lock" feature that keeps it up or captures the arrow.
Start with the basics. Make sure arrow is 90 degreesto string.Adjust rest up and down until arrow is at right angle to string. (Assuming knock point is still good.)Have someone hold the bow, stand back,and line up the string with the cam wheels, then move rest left or right until arrow is in perfect alignment with string. This is setting your center shot. At the same angle, align sight pins with string also. Then shoot at 5 - 10 yards. Adjust sights to dead on. Then move back 5 yards at a time and repeat sight adjustment until you are at 20 yards. Should spare the neighborhood.