To determine the best placement for a display ad promoting affiliate offers, focus on relevance, visibility, and audience intent. Analyze website traffic sources and user behavior using tools like Google Analytics. Choose platforms and pages with high engagement and content aligned with the affiliate product. Position ads above the fold or within content to increase visibility and click-through rates. A/B test different placements and formats—such as banners, native ads, or sidebars—to identify what performs best. Optimize for mobile users and ensure fast loading times to reduce bounce rates. Ultimately, success lies in targeting the right audience at the right time, on platforms where they are most likely to trust the content and act on your recommendation.