[jbs789]

I often think about the idea that a good design takes information from the world (or the users head) and puts it into the system, reducing cognitive load. So if a door needs to be pushed, put a push plate on it, rather than requiring the user to remember to push the handle. Think about it when labelling buttons quite a bit, for example. Or workflows.

[smusamashah]

Or even when writing code, think about whoever is going to read or use your code.

Another idea was about suggestive nature of design. If top of a small wall is flat, practically it's asking you to put your empty can on it.