I've been making great strides in improving my stamina when we go shooting at the indoor archery range. The first trip, I think I was able to pull off 6 shots before my arms were tired. The muscles quickly tire until you learn how to use them in this way. On this day, our second outing, I was able to pull off 30 shots before my arm started to tremble under the strain of holding the bow out in front of me. I was shooting well, I even put one almost squarely in the center of the bullseye.
I stayed at the ten yard line for most of the time, but then tried my hand at 20 yards. Once I was able to dial in the sight, I was shooting fairly consistently.