The rise of large-scale readily available AI models brings new possibilities and unique challenges.The stack and skills required by AI engineering have similarities to and key differences from traditional ML engineering. AtZalando, we’ve been innovating and developing the Fashion Assistant with the ChatGPT LLM since last year. We’ll discuss prompt engineering, few-shot learning, Retrieval-Augmented Generation (RAG) and model evaluation - what they are, when and how to apply them when building applications with LLMs and some of our learnings.