I've decided to make the one large city on the region map (roughly Mitte, the center of Berlin in the real world) into a large railroad junction. For this, I'll need a lot of railroads coming into Mitte so building rail towards Mitte will occupy me for quite a while. First I want to extend the line along the river to Berlin. I started with Wilhelstadt.
First, I extended the rail and highway to the edge of the map. I planned for the next village to be on the lake in the east. The overall plan was straightforward with industrial areas on the railroad, residential away from rail and avenues, and a mix of commercial and residential inbetween. However, after the endless advisor whining for trees, I decided to conserve some more forested areas to see if it helps. The elemetary school interestingly became an environmental magnet school in between a small forest and the lake. I used some further reward buildings, including City Hall and the minor league stadium, to help buffer the industry from the rest of the town. Here's a picture of the industrial region.
I also wanted to expand the resort area to the south. I placed a bunch of beaches along the river. Because I tend to build a mix of low and medium residential but mostly medium density commercial, my demand was mostly residential, so I built most of the village as medium-density residential - a "cheap beach" to complement the nicer area to the west. Again, I tried to conserve trees. The area developed quickly, although more heavily low-income than I expected with all those beaches. Jobs are a problem and I'm going to have to work on the transit soon.
Finally, here's a pic of the developing region