This document provides best practices and guidelines for writing HTML code, including:
- The importance of front-end code on user experience.
- General guidelines like applying consistency and designing before implementing.
- Details on HTML document anatomy like specifying DOCTYPE and including metadata tags.
- Tips for semantic authoring, common elements, attributes, and accessibility/usability features.
- Common mistakes to avoid like forgetting to close tags, incorrect DOCTYPE, improperly nesting tags, and more.