I have heard it time after time:
“My kid can throw the football a country mile.” 
“He has got a cannon for an arm.”
“He throws a great deep ball.” 

That is all good, BUT is he accurate? It means nothing if he cannot hit his intended target on the run and squeeze the football through a window the size of a bar room dartboard. 

Not only that, but can you be accurate while speed freaks are trying to vaporize you while you are looking downfield for an ally. Defensive pressure is a truth teller on accuracy.

Yeah. This is where the herd of cannon arms starts playing a different position. So, the question is how do you obtain serial perfection throwing the football. Answer: throw the ball over and over again. Remember there are only 32 starting quarterbacks in the NFL.