This document outlines best practices for mobile site design based on a study by Google and AnswerLab, which analyzed user interactions on various mobile sites through 119 usability sessions. It identifies 25 key design principles categorized into five sections: homepage & site navigation, site search, commerce & conversions, form entry, and usability & form factor, emphasizing the need for clear navigation, goal-oriented features, and mobile optimization. The study highlights user expectations for seamless, efficient, and immediate access to content on mobile devices.