use a cognitive-mapping tool, such as thortspace.
A phenomenology of effective problem-solving
Andrew Bindon

While thortspace is pretty cool, the mapping tools I use vary. By this, I mean I’ve used many tools, however I’ve settled on a mapping tool named TheBrain. It’s pretty freeform, but not as freeform as thortspace.

A screenshot of my map created using TheBrain. It’s mostly personal.

I won’t go too in-depth on what TheBrain actually is, so just go to the website and try it out. You get a 1-month trial for the pro version, but I’m absolutely fine with using the free version.