In most texts the creation itself is a little overlooked or we get flash views of cities well after they were made.
While I understand naturally growing cities that are consequences of people coming together, I'm most curious about how a ruler decided a new city will be built and understanding what went into that. For example Alexander built twenty new cities that bore his name, or so I've heard, but what was this process like?
Was an ideal spot pointed out and citizens were given orders to move there? Were there financial incentives? What was usually built first and so on.
What time period and geographic area are you interested in?
The key things generally speaking are; the fertility of the land and how defensible the area is. Then things like; is it on a trade route, what valuable resources (if any) are nearby, what is the climate like and disposition of the natives. But really the key thing was the value of the land, there's few exceptions where a city is founded on bad land- Massalia being one.
Alexander the Great founded 70 cities which bore his name, and also named one after his horse when the poor thing died.
Another interesting point, when Hephaestion (who if you didn't know, was Alexander's best friend and possibly lover-IMO almost certainly lover) died, the funeral cost around £1,500,000,000 in today's terms.
Source ; I study ancient history.
EDIT Just to be clear I only study Greece and Rome (with a little Egypt thrown in now and then), so what I described were the key things for the Greeks, though it is a safe assumption that they were the same across the globe.