Start here. This is the direct spoken answer to practice first.
Overview
The best first feature proves user value while keeping the consequence of a model mistake small and observable.
I choose a narrow, reversible use case such as drafting a support reply or summarizing a document, not an autonomous high-impact decision. I define success and unacceptable failures, identify the allowed data, create a representative evaluation set, and keep authorization and state changes in application code. The model output is clearly labeled, validated where possible, and easy for a user to edit, reject, or bypass. The existing workflow remains a fallback.