What are the most basic requirements best practices?

There are few basic requirements best practices:

Document the "what" and not the "how"

Verifiable - have your QA group review/approve your requirements

Let the Stakeholders state the requirements, not the Business Analyst

Requirements should be approved by Stakeholders

Stakeholders should prioritize requirements

Requirements should undergo "change management" after approval

Requirements should be "traced" to downstream project deliverables like design documents and test cases.