Ahhhh

For City maps, I always do a pencil/paper sketch. Rough out the area the city should be in. Find/place a good central origin point ( a castle, market square, major temple etc), and then just radiate some 'spokes' out from there. Then much like a spider web, draw in cross streets, and then alleys from there.

Remember also, a realistic fantasy city will never be rows/streets of individual houses buildings, but clusters of joined buildings (look at Google Earth satelite views of the old parts of any European city to see what I mean). Almost every block with have a central courtyard they enclose for gardens/privys, etc. These clusters will then start to form alleys as buildings build against each other.

Also, major thoroughfares will form from city gates strait towards the central point in your cities, as well as along the shores of any lakes, rivers, and coastal portions.

A large collection of my old (20+ years) pen-n-paper city maps can be found here: http://www.cartographersguild.com/sh...Pen-n-Paper%29