You guys should naturalize a few players from neighboring countries, maybe a Brazilian or two, get a good coaching staff, and try to find natural Pakistani talents born outside of Pakistan. Kind of have to play around until you can get something going.
Remember it is not about size. Russia has a decent population but doesn't perform to expectations. On the other hand a small poor country like Armenia smashed Denmark into pieces at their home too I think.
Ultimately IMHO I think if you can get good youth programs (invest in it) maybe it will ease things over time. It will take awhile but the results should probably come around slowly but surely.