So you always wanted to loot like us big dogs? Well in these few steps ill show you how
So first thing is first setting up your army correctly and using the benefits of your legion
If you pick heros that are carriers to be your legion leaders you get a increase in how much the overall carrying capacity of the army can hold
As you can see in this picture he increases my carrying capacity by 327% this in turn makes it so i dont need as many carriers per army
As you can see now my carrying capacity is over 4 billion resources which is perfect for looting cause generally most fallen cities have no more than 1billion of each. As you can see as well i didnt need as many carriers to have that much of a capacity
Also your going to want to search for fallen cities that are untouched 200 attacks left that just happened right after the earthquake but you can also find some that are 180 160 140 120 100 80 etc still have good amount but not s great as a 200
The fallen cities start off at 29 days 23 hours and time starts counting from there
So happy hunting 
hope this helps you loot alot more.