Clear principles for a maintainable REST API: pagination, filtering, evolution

[Violet_W]

I'm redesigning a legacy internal REST API that has become a tangled mess of inconsistent endpoints, unclear error handling, and multiple versioning strategies. I want to establish a clear set of design principles and standards for the new version that our entire development team can follow. Beyond the basics of using nouns and HTTP verbs correctly, what are the most important but often overlooked aspects of designing a maintainable and developer-friendly REST API, particularly around pagination strategies, filtering/sorting conventions, and how to gracefully evolve the API without breaking existing clients?