On-page SEO factors are everything you can optimize directly within your HTML and content to help search engines understand and rank your pages. These break into technical elements, content elements, and user experience signals. The core technical factors include your title tag (50-60 characters, keyword-front-loaded), meta description (155-160 characters to maximize click-through), URL structure (short, descriptive, hyphens not underscores), canonical tags to prevent duplicate content issues, and header hierarchy (one H1, logical H2-H6 structure). Schema markup has become non-negotiable for competitive queries since it directly feeds rich results. Content factors cover keyword placement and density, semantic relevance (LSI keywords and topic coverage), content depth (we typically see 1,200+ words rank better for commercial queries, though this varies wildly by intent), multimedia elements like images and video, and readability signals. The keyword should appear naturally in your first 100 words, at least one subheading, and your conclusion. Internal linking matters more than most clients realize—we aim for 3-8 contextual internal links per page to distribute authority and clarify site architecture. User experience factors now heavily influence rankings. Core Web Vitals (LCP under 2.5s, FID under 100ms, CLS under 0.1) directly impact your ability to rank since the 2021 page experience update. Mobile responsiveness isn't optional—Google's been mobile-first indexing since 2019. HTTPS is table stakes. Intrusive interstitials will kill your mobile rankings. Image optimization involves descriptive file names, alt text with natural keyword usage, proper compression (we target under 200KB for most images), and next-gen formats like WebP. At Ottawa SEO, we audit these factors in clusters—fixing technical issues first, then content gaps, then user experience friction. A site with perfect on-page SEO but weak backlinks will plateau around position 8-15 for competitive terms. On-page gets you in the conversation; off-page and authority push you to the top three.