Sometimes it's quite interesting to take a development guideline and see how far you can apply it, and what other recommendations emerge from it or are subsumed by it.

I first tried this while doing a code review many years ago. There was a gratuitous asymmetry in naming between two operations: Attach and Close, IIRC.

I then did most of the rest of the review based on the question of symmetry (although I didn't share that with my colleagues 🙃), looking to improve the symmetry of the code or understanding what the underlying cause of an asymmetry was.

It was surprising how effective and insightful this fulcrum was.

This carried over into some of the subsequent code I wrote. In general it was to favour symmetry, but that was not an assumption.

I approached it as "What would symmetry mean here? What would asymmetry mean here?"

Finding necessary asymmetries also clarified a number of design issues and simplified a lot of interfaces and implementations.

Another guideline I have been testing the boundaries of is DRY. This is not a universal or absolute principle, as some developers think, nor is it simply about duplicated code.

Consider it as an enquiry into the role and necessity or superfluity of repeated information, with a strong skew towards reduction of duplication — whether that is duplication of intent, information, etc.

When you lever your view of code through the fulcrum/razor of DRY then reduction of comments, extraction of methods, replacement of enum/switchs with lookups or polymorphism or callbacks, etc. falls out as a natural consequence.

Likewise, avoiding prefixes like get, test, check, etc.

And also the use of type deduction, i.e., instead of

ClassName a = new ClassName();

prefer

var a = new ClassName();

DRY can be quite a productive line of enquiry.

@kevlin I find myself wanting to be a bird on your shoulder through one of these code evolutions, because what becomes clear in working with the shape of source code may be obscure in either the text of the beginning state or the end state.
@kevlin I am reading Your Code as a Crime Scene, which takes a forensic metrics approach to source code health and evolution, so "when code changes, is it better?" is at the top of my mind.