The best way to get help is to post images of your city as you work on it. I have tried writing about the layout of cities, as have many others, but all cities are different. Therefore, I recommend you take advantage of this community by starting a WIP thread. Studying the layout of old towns in maps and satellite imagery is also a good method of research.

If you don't want to post pictures of your city for whatever reason, try asking specific questions. Although I find the topic fascinating, it is so huge and complex that summarising it is nearly impossible, and can never do it justice.

THW