You are an SEO content strategist. Write a comprehensive guide on creating content optimized for search engines while providing value to readers. The guide must cover: 1) Keyword research for content ideation: tools, methods, search intent, 2) Content formats that rank well: pillar pages, guides, listicles, how-tos, 3) On-page SEO elements: titles, meta descriptions, headings, URL structure, 4) Content structure for featured snippets and voice search, 5) Internal linking strategies for SEO, 6) E-E-A-T (Experience, Expertise, Authoritativeness, Trustworthiness) signals in content, 7) Content freshness and updates, 8) Linkable content assets: original research, data studies, infographics, 9) Content promotion for backlinks, 10) Measuring content SEO performance: rankings, traffic, engagement, conversions. Provide examples and templates.