I am wondering how tight my group of arrows should be? Sometimes I get a arrow thats off from the rest of my arrows. Also when I am shooting at the range I keep thinking to myself what happens if I mess up while out in the field and hit the deer in a non-vital area.

A couple of inches won't hurt that bad but if your 6 or more you need to work on that. Make sure those arrows are straight.

After you shoot for some time and on a fairly regular basis I know of alot of folks who strive for specific inch groups at respective yardages. For example, 1 inch groups at 10 yards, 2 inch groups at 20 yards, etc......

Personally, I think a 4 inch group or so at 20 yards to be very respectable for most folks.

You might want to number all of your arrows so you will know if it is the same arrow that is shooting out of the group. If it is , rotate the knock 120 degrees and see if it comes back into the group.