Start by building ten warehouses (you can the destroy them):
Build one of each toll building type (no need to connect to your road network):
Next, we'll go ahead and build some post offices. I built 7, on the N and S sides of each grid square. I also built a sorting facility on the W edge of the city. This is looking towards the West.
It will take a while to send enough mail, but we can just let them do their work while we work on the industrial areas, and eventually get:
PostmanDeliver 1 000 000 units of Mail

We need to build one of each type of industrial area and get it up to level 5. This shows where I placed each one (camera is looking E by NE):

From left to right they are, oil, wood, farming, ore. Oil,ore, and food all need to go on areas with the right natural resources. More resources means they will level up faster. But even worst case, they will import the raw materials and process them and you will make some progress, just slower. For all of them it is worth turning on all of the industrial area policies (you can access these when inspecting the area). I'll provide some specifics for each type of area. To get them up to level 5 you will need to get at least 800 workers and process 135000 units of resources. When you view the info for the area, it will show where you stand. You will probably be okay on the worker side of things if you have capacity for 2000 workers. You may need a bit more or less depending on thef5 state of your city. If you have trouble you could always focus on one of the area types at a time, and once it hits level 5, sell off the majority of the buildings (but don't sell the HQ or delete the area).
I built most of the areas with the same 2x1 block street grid as the normal city. You can designate the area with a painting tool, and once you've done that you need to build a headquarters of the appropriate type. Here are some specifics on each type of area. You may want/need to level out the areas where you will be building beforehand to make things a bit easier.


Oil: I built small oil pumps up and down each side of the blocks. I built them on both the E&W edges of every block, but you may want to space them out a bit (maybe just one side of every other short block). If you place them too close together you will just use the resources up too quickly. The insides were filled with oil sludge pyrolysis plants, petrochemical plants, and worker barracks, as well as storage areas. I would probably aim for a storage area in every other block, I did one on each which I think was overkill. You can replace with a storage cavern later, but don't just scrap them without emptying them first. Don't want to lose that black gold! You should also build 20 worker barracks throughout the area, more than that provide no further benefit.

Ore: I used larger blocks for this (2x4), because the buildings are quite large. I placed 3 small mines (and later upgraded them to small underground mines) in each block. 2 ore grinding mills processed their output, along with a small storage area (you unlock a better small one later on which you can replace it with). You can also fill in worker barracks in the remaining space until you hit 20.

Farming: This won't run out like ore/oil, but you do need to be in an area with the fertile soil in order to produce output. I built small crop fields, along with small pastures (and later flour mills) to process the resources. I put a few silos on the ends of the blocks to store the excess. You want 20 worker barracks again, but they are pretty small so placing them should be no problem. I will note that the area I built in had big differences in output for the farms just by moving a small area. I filled in about half of the area with farms, focusing on placements that could produce at least 15 per week. Then I built barracks, pastures, and mills in the areas that weren't as good for farming.

Lumber: One special thing about wood is that you can create the resource by planting trees, so before building anything, go nuts and plant tons of trees in each block before building anything. As far as the actual buildings, use small tree plantations (and replace them with sapling fields once they are available). Sawmills and later biomass pellet plants can be used for processing. Half the blocks I did 3 tree fields and a sawmill. The other half, I did 2 tree fields, a biomass pellet plant, and a sawdust storage area (these don't unlock until level 2, so you'll need to use the wood lot storage area at first). The worker barracks are pretty large, so I built mine around the outskirts of the area.
There will be a bit of waiting as you wait for all four areas to produce enough resources to level up. Once the first one hits level 5, you will unlock:
Once the oil area hits level 5, you can make a new oil area near the shoreline and build 5 offshore drills (you can delete/destroy the area afterwards) to unlock:
While you are waiting, you can build 6 more industry areas (they don't need to level up at all, you just need to build a HQ) to get:
Once all 4 of the areas have hit level 5, you will have unlocked all of the unique factories. You need to build them all. Some are very large, but it doesn't really matter where you build them (they don't need to be placed in the industrial zones). This will get you the last achievement:
If you actually care about them beyond the achievement, you should place them as near as you can to the resources they will use.
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