How we change what others think, feel, believe and do
Use to remember a complex and detailed set of information.
Become a town builder. Start from the square in the middle of the town. This is the core of the system you are seeking to remember. Build a statue, fountain or something else here to remind you of the general theme of what you are remembering.
Then create roads going off in all directions to represent the major strands of knowledge. Make the roads similar in some way to the subjects or put something at the entrance to remind you what they are. Then put things down the road to remember. Have side roads and smaller roads off these to show sub-categories.
An alternative approach is to map your system onto an existing town.
Use other memory systems within this, for example having houses that contain sub-systems.
I am building a town about music knowledge.
In the town square is a band playing. One road has a pile of rocks at the entrance, signifying rock music. Another avenue leads straight off the square, with a marching band stepping down it, playing jazz. A few steps down is a store front selling saxophones with one of each different type of sax in the window, each on different and related background. A narrow road goes off to the side of the shop with jazz clubs, each playing different types of jazz.
... and so on.
Creating a town system uses visual memory in a similar ways to other methods, creating concrete representations of things and concepts you want to remember. The physical dimensions allows you to link things together, so one memory leads to another.
The town can be as large as you like and, like normal towns, you find it easy to navigate around without having to think about all places at the same time. In fact all you have to do is know the next step and see the next thing.
You can navigate around the town in various ways. You can walk, take the bus or subway. You can create short-cuts from A to B with your own science-fiction 'transmat' wormholes. You can also float up into the air and see the whole system like a giant mindmap, floating down to see more detail in areas of interest. Or you can carry a map around with you (you can even draw a physical, real-world map).
Beyond towns, you can create an entire country, with towns covering particular domains of knowledge, with rail, air and 'instant transfer' links between them. And beyond countries you can have an entire world or worlds or universes of knowledge.