I've had a lot of luck following tutorials for fantasy mapping such as overland, and a few local regions. But I haven't the faintest clue how to start making a decent looking city street using gimp. I was using dundjinni but it is so outdated now as to not work on my computer

I'm the ZM in an AFMBE campaign set in Vancouver 2010 Olympics. (I live in the lower mainland so I know the area very well) I would like to start mapping off areas such as east hastings and gas town. Can someone give me a few tips on where to start. Maybe a palette?

Any help would be very appreciated. If I can get some really good maps going for my campaign I would be more than happy to share them with the community.