Excellent advice! When I know my setup is right and all of a sudden my arrows start "flying" it is usually because I am trying to hard. I want every arrow to robin hood the last arrow. Some immediate remedies that have worked are:

Make sure I am loose and not squeezing anything.

Just shooting the arrow as soon as the pin is "close". Basically you stop trying to be so precise with your aim and just relax and let arrows fly. Sometimes it is amazing how the groups tighten up when I am not even "trying".

Pick a bigger target. Instead of the x I will just worry about getting it in the "pie plate". This also keeps me from "trying to hard" and makes me relax.

But when those remedies do not work:

A non-immediate remedy that always works is taking some days off shooting and spending that shooting time with my wife and/or daughter. It gets my mind off of shooting and the next time I shoot I am much more relaxed and loose.