This chapter explores the fundamental principles of effective prompt design, an essential element in prompt engineering. Unlike specific techniques, these principles are versatile, applied across diverse AI models and contexts, and they possess enduring relevance. Key topics covered include clarity, specificity, and conciseness, which collectively enhance the quality of AI interactions by eliminating ambiguity and over-complication. The chapter also emphasises the importance of providing contextual information, incorporating instructional details, and leveraging domain knowledge to optimise the relevance and accuracy of AI outputs. Readers will learn to utilise action verbs, specify output formats, and use examples to guide AI responses effectively. Structural considerations, such as prompt templates and component separation, are highlighted for their role in improving clarity and coherence. The chapter concludes with insights on iterative refinement, creativity, and staying updated with advancements in AI, providing readers with a comprehensive framework to craft prompts that generate precise, relevant, and innovative results. This guidance empowers users to harness AI’s full potential across various domains, ensuring interactions are both efficient and meaningful.