Diagramming.

I'm serious.

The more I (as a developer trying to master design) delve into the product design space. The more I see that there is no more fundamental skill in design than that of constructing 'information architectures'. Essentially, mapping (or diagramming) the most important pieces of a design that you are making.

It is literally the key to creating a great design.

I wrote more about this in a guest post here: https://simpleprogrammer.com/information-architecture-develo....

Think about the design of Apple products, is it really just the way they look that makes you love them. Or is it more subtly, the way the work (of which UI is a component), and how that makes you feel?

Definitely worth thinking about.