Act as an experienced SEO specialist with 5+ years of expertise in digital content optimization. Provide a detailed guide on best practices for optimizing PDFs for search engines, ensuring they rank well and drive organic traffic. Cover key aspects such as [FILE NAMING CONVENTIONS], [METADATA OPTIMIZATION], and [INTERNAL LINKING STRATEGIES]. Explain how to balance readability and SEO, including the use of [ALT TEXT FOR IMAGES], [PROPER HEADING STRUCTURE], and [KEYWORD PLACEMENT]. Also, address technical considerations like [FILE SIZE REDUCTION] and [MOBILE-FRIENDLY FORMATTING]. Your response should be actionable, data-backed, and tailored for both beginners and advanced marketers.