Efficient Power BI developers design visually impactful dashboards by focusing on clarity, usability, and storytelling. They use clean layouts, consistent color schemes, and branded themes to enhance readability. Advanced visuals like heatmaps, KPIs, and decomposition trees are employed for deep insights. Power BI developers use dynamic elements such as slicers, bookmarks, and tooltips for interactivity. They prioritize critical metrics and reduce clutter by avoiding unnecessary visuals. By tailoring designs to the audience and purpose, developers ensure dashboards are not only aesthetically appealing but also effective in communicating insights.