Start with Google Search Console and confirm the site is indexed, then check for Coverage errors, manual actions, and security issues. Run Screaming Frog or Sitebulb to crawl the entire domain and flag broken links, redirect chains, orphaned pages, duplicate content, missing metadata, and crawl depth problems. Export the crawl and filter by status code—301s and 302s over three hops waste crawl budget, 404s on important pages need immediate fixing. Next, evaluate Core Web Vitals in PageSpeed Insights and Chrome UX Report. LCP should be under 2.5 seconds, FID under 100ms, CLS under 0.1. Real-world CrUX data matters more than lab scores. If you're failing on mobile, check image formats (WebP beats JPEG), lazy loading, render-blocking JavaScript, and server response time. Canadian hosting on slow shared servers routinely tanks LCP by 800ms or more. Check mobile usability in Search Console and test the site on actual devices—viewport issues, tap target spacing, and font sizing problems still slip through automated tools. Run a structured data validator to confirm Schema markup for breadcrumbs, local business, articles, or products is error-free. Missing or broken Schema won't tank rankings but limits rich result eligibility. Review robots.txt and XML sitemaps. Confirm high-value pages aren't accidentally blocked and the sitemap includes only canonical, indexable URLs. Check canonical tags across the site—self-referencing canonicals on all pages prevent duplicate content issues, especially on paginated or filtered category pages. At Ottawa SEO, we segment findings into critical (blocks indexing or causes errors), high-impact (directly affects rankings or UX), and optimization opportunities. A 50-page local business site might surface 12–20 issues; a 5,000-page e-commerce site can easily hit 200+. Prioritize what actually moves the needle—fixing a sitewide canonical mistake beats optimizing alt text on footer logos. Track changes in a spreadsheet with issue, priority, owner, and completion date so nothing falls through when you're managing hundreds of fixes across a portfolio.