Practical lessons on prompt engineering in production settings, drawn from real LLMOps case studies. It covers key aspects like designing structured prompts (demonstrated by Canva's incident review system), implementing iterative refinement processes (shown by Fiddler's documentation chatbot), optimizing prompts for scale and efficiency (exemplified by Assembled's test generation system), and building robust management infrastructure (as seen in Weights & Biases' versioning setup). Throughout these examples, the focus remains on systematic improvement through testing, human feedback, and error analysis, while balancing performance with operational costs and complexity.