Hey guy's I'm looking to make a map for a D&D campaign of a city, i've had a little bit of experience making urban maps before but not to this scale.
I would really like to make one like this Casale_Monferrato_map_(018_003).jpg but am unsure how to go about it?

I would really appreciate it you could either give me some clues as to how to go about it or even better a tutorial
I've had a hard time trying to find a Tut that will suite my needs also I primarily use PS to make maps.

Cheers,