City Planning Help

[Silvis]

I have been playing Civilization since CivII and I have to tell you that this problem didn't really start occurring until Civilization 5. When building my cities I usually improve the plots to maximize what they are the best at (i.e. grassland = farm, hills = mine). However, I have noticed that in Civ5 you cannot rely on that to help with production. I have built many cities with great production, but they seem to want to focus more on building the food for growth than anything else and if I attempt to make them focus on the production they starv. This causes me to have a limited army size and normally my demise, unless I get a good spot. Can anyone help me out and give me some tips on building some good production and gold cities. It would be a great help!