I am not sure that he can learn to throw deep bullets like Mike Vick or Drew Brees because that seems to be a God given talent and it is something he has never had the ability to do it. If he could do it, he would have definitely been a first round pick or second round pick and not a third rounder. Foles is a perfect west coast offense quarterback.
Foles or Chip should be reducing those deep throw plays. Also Desean Jackson is not there who has the speed to bail him out with the overthrows. Those lob overthrows will not work with the wide receivers he has and he or Chip has to adjust the plays to exploit Foles' strength as a passer (which I am sad to say is not the deep ball)
Check out the NFL combine Scouting Report on him
http://www.nfl.com/combine/profiles/nick-foles?id=2532842
That scouting report is him down to a tee
This year in each game so far, I am seeing at the very least least nine throws deep by Foles which is way too many for him. He did not hrow nearly as much deep throws last year.They are probably compensating with the deep balls because of the lack of a running game and opposing defenses stacking the box and playing zone in pass coverage.
Which makes me wonder if Chip and Shurmur are using the Tight Ends Like Ertz, Celek, Casey and Burton more to combat this (when defenses do this you exploit them up the middle in the pass game with the tight ends). If they are not I really think they need to employ the two tight end sets more with a single running back in the backfield if defenses are doing this but I digress