When all your enemies are beaten and a Division of Armor units siege the last city of your last opponent, time is right to develop your civilization.
You should only need 5-7 cities to get control of the world. Do not build more cities until you discover Railroad.
After the invention of railroads you should starve cities you do not need anymore away to optimize the map. Make sure that before building a nee city you build railroads on the spot to get the full possible bonus. You cannot railroad a square where there is already a City on it.
Yes. While you get control of the world with units, find the spot where a nice capital region could be cultivated. It should have one good shield-producing citysite, and one good trade-producing citysite. No matter which site you want to be the future capital of your second, reimagined empire, found the first New City on the trade-rich site. After it's railroaded, found the city and pound Caravans into ColCop, the Colossus and Copernicus Observatory. One by one, get to 6 cities in your new capital region, then start to kill off your original 5-7 cities by starvation.
Only by railroading your ancient cities. But take care you do not starve away your world wonders. Even better to build wonders in only one City which is perfectly placed on the map and is situatet in a Forest/plains area for higher Production.
Never build a wonder in a city which you will have to starve to dust. So, never build a wonder until you have the Railroad. You will never find a city "perfectly placed" among your first 5-7 cities, you need a global view to plot out your 128 citysites.
The hard part is preventing the AI cities from building wonders while you play. To do this, you need to introduce an irritant to each of the rivals civs. Discover them by land and sea as soon as you can, and lodge a unit within view of their capital. Like a grain of sand in an oyster, the very presence of your lowly Militia in the mountains within the fat-cross view of Athens will make Alexander forget all about Wonders.
Pestering your rivals overseas is obviously going to take more time, so my tech ride always goes for Horseback Riding -> Map Making. Then, 2-move Cavalry have a much easier time meeting up with a boat. You have to irritate the rivals early, so they don't build wonders. Even if you're in no position to challenge the Romans halfway around the world, drop a Cavalry in their back yard, later replace it with Diplomats, and you'll have the time you need. They won't build Wonders before you've got your Second Empire up and running, on railroaded citysites.
