Klaviyo released a comprehensive guide on prompt engineering best practices specifically designed for marketing teams in 2026 (Klaviyo Blog - AI). The 10 tactics are grounded in real-world testing across lifecycle flows, campaign copy, and retention programs for ecommerce brands in lifestyle and apparel.
Key practices include starting with a hook before writing the prompt itself, articulating both product features and emotional benefits, and pinpointing the customer's journey stage before generating copy. According to the guide, one fashion and apparel brand achieved a 2x conversion improvement in win-back flows by providing more specific customer context to the AI (Klaviyo Blog - AI). The guide also emphasizes building reusable prompt frameworks with fixed brand voice elements and variable inputs, which enabled one team to produce briefs and copy 4–6 weeks in advance rather than manually building them week-to-week (Klaviyo Blog - AI). Implementing a "do not" list in prompts reduced editing time by roughly 60% for practitioners, while centralizing brand voice across teams reduced copy editing time by 20–30% (Klaviyo Blog - AI).
For commerce teams scaling AI usage across multiple channels and campaigns, the guide stresses the importance of shared memory systems—using cloud storage or workspace connectors to maintain standing references so teams avoid re-briefing the AI at each session. This approach compounds over time, enabling loyalty programs, campaign calendars, and audits to build on previous work without starting from scratch.