TheHoarseWhispere - great set of posts about worldbuilding!
I'd like to add a couple of things, if I may ...
The first is trees. Or, rather, the lack of them. The effects of settlements on forests is huge. If you ignore settlements constructed as part of a defensive line or in order to mine a particular mineral then most settlements start life as some kind of market for either goods or people. The inhabitants will need houses, workshops, stores, barns, etc. These may come to be built out of brick (or out of quarried stone if they are rich enough), but often these will be made from wood. If you think of roundhouses they are made primarily of wood, and thatched. Fencing is normally formed of wood. All these wonderful hand-built homes will also require heating. Granted, later towns may use fossil fuels of some kind or another, but the vast majority will be using wood fires for heating and cooking.
The pressure on local forestry will be immense, and areas very quickly become denuded. This is great (after a fashion) for local farmers who gain more land for crops and animals ... but I often see on maps (and I am not having a pop at anybody at all when I say this) cities and towns surrounded by huge swathes of thick, pristine woodland. In my experience, and if you look at satellite images of towns and villages, the predominant land use around settlements is open fields.
The second thing is ... waste disposal. Sanitation. Its a dirty word, but somebody has to do it. (I feel I should apologise for that ...) Granted, there is evidence that the Indus Valley civilization had "urban sanitation", and Rome certainly understood the concept of sewers and whatnot. However, primarily it wasn't until the late Middle Ages that sanitation was found again in settlements. Had Ancient Rome not 'fallen' then perhaps it would've been different, but if you look at examples from today's developing nations then its clear that sanitation is something that not every civilization grasps fully. (I could make a really bad joke about the 'bottom up' method ... but I won't ....)