Caedo wrote:However, that works only up to size 8. You can't grow a city bigger than size 8 like that.
To make your cities grow quickly invest in entertainment, trade, and luxury to the point that your city is celebrating. There has to be no unhappy or angry citizens. There has to be at least 50% happy citizens.
First, plan on having at least one trade route with the city, preferably more. Your bank balance will appreciate that.
Second, plan on having at least four of the following, temple, marketplace, coliseum, bank, cathedral, or, stock market.
Third use entertainers to make unhappy citizens content (which is between unhappy and happy).
Fourth, use the tax rate to give at least 20% probably 30% of your revenue to luxuries.
Fifth, be a democracy or a republic as your form of government.
Finally, a wonder that helps with happiness for your entire country (Women's Suffrage, Genetic Engineering, etc) never hurts.
What happens when the city has at least 50% happy citizens and no unhappy and no angry citizens? They celebrate by growing one citizen every turn. This assumes that the surrounding territory has sufficient food resources to feed that growing city. It's hard to grow a city in the desert that fast, but easy in grass lands. You'll be using your workers and settlers to irrigate the surrounding territory to increase the amount of food. You may also have to learn refrigeration and buy a supermarket.
I've had many cities grow from size 6 to 25 in 25 turns or less-it takes a lot of care and feeding, but definitely doable.
Late in game, I can use both techniques ( adding settlers till it grows to size 4 and buying infrastructure & freight to produce happiness) to grow a city from size of 1 to 20 in 25 turns. There's a reason that the default infrastructure/building for a brand new city is airport (when you have learned radio). You have another grown city primed to build three settlers, a rifleman, an engineer, and a freight, ready to fly them in. I usually have enough funds to buy one of these units on each turn, and fly them in during the next turn. Also, if I conquer an enemy city, I built an airport and fly in enough settlers to grow it to size four, buy the necessary infrastructure, and within a few turns the city is far larger than before.