One thing I always find difficult is to make full use of the production of my cities. Take Amsterdam ( see attachment ): There I have lots of mines which I very much like to use, but as soon as I let a citizen grow ( to produce a new circle ) I am unable to use that circle for production, because the new citizen costs food and thus I have to put the circle on a food-square 
I have the strong feeling that I do something wrong; tell me, what is it?

I have the strong feeling that I do something wrong; tell me, what is it?

