How many of each Resource spot should I build?

Army Camps and Farms:

I only have 1 of each as they are requirements of other building upgrades. Its unrealistic to keep food production in line with your troop upkeep so why waste precious spots on a bunch of farms? Same goes for the Army Camps, you get much bigger boosts to training capacity through research and duty generals later on down the line so why have more than one Camp?

Everything Else:

Here you have quite a bit of wiggle room and get to make some choices. Its usually a good idea to max out the number of tiles for the resource associated with the troop type you are focusing. So if you're a boss runner and you have to heal cavs all day, you might want to focus Iron Mines. If you're an Archer heavy PvPer you'll want a bunch of sawmills. If you're a siege tank defender, you're gonna need boatloads of stone for rebuilding siege.