City Population & Settlers

How does a city increase its population?  I see my pop growing, but can I accelerate the growth?

Once I have enough pop to build a Settler, where can I establish a new city (distance limits between cities, terrain limits, etc)?

Thog wrote: Building give you population according to their grain consumption. If the building costs 5 grain p/h it gives you 5 blokes for your town. Building buildings that are heavier to upkeep boosts your population faster than the ones with low upkeep.  I believe there are no restrictions regarding your second question.  Somebody please verify that.

Yes to both.

City Population = Food Consumption by workers in that city

And yes, there are no restrictions on where you can settle your second city with the exception that:
a) the square must not already have a city on it
b) the square must not be "unsettlable" (marked on the map as having zero wood, clay, iron, stone & food) and usually also indicated graphically as "unsettlable" by being a lake, or a Volcano or something similar.