I decided yesterday to build a city. Here's how it's going so far...

Phase 1- Terrain. I spent 10 minutes in World Painter creating an island surrounded by high cliffs. Don't let anyone foll you into thinking terraforming is hard, because it's not (in most circumstances).
Done, until phase 3.

Phase 2- The river. The only way into the city is by river, so I am going to spend a great deal of time making sure everything along it is perfect. The arch is the pictures is at the city-end of the of the river.
Started, with some overlap into phase 3.

Phase 3- Integration. I will also need to integrate the river and the rest of the map into Minecraft's natural terrain.
Not started.

Phase 4- Citadel. On the island, there will be a main castle/citadel which I will build before the rest of the city. I will also build the city walls during this phase.
Not started

Phase 5- Buildings. I will create several kinds of buildings and place as many as I can around the island.

Phase 6- Decoration. Here, I will neaten up any mess, create paths, gardens, make the mountains more realistic, and probably add some boats too.

Latest report:

This will become an adventure map! Hopefully it will attract more downloads that way. In the meantime, I have provided a download of the terrain (and a few buildings). Please note that the map is still a heavy WIP, there are entire chunks randomly missing, it will get better! Also, any advice is welcome.