The essential meta tags for SEO are title tags, meta descriptions, viewport, canonical, and robots directives. Title tags carry the most weight for rankings and should stay between 50–60 characters to avoid truncation in search results. Meta descriptions don't influence rankings directly but control your snippet text and click-through rates, so aim for 150–160 characters with a clear value proposition. The viewport meta tag is mandatory for mobile-friendliness, which has been a ranking factor since 2015. Canonical tags tell Google which version of a page is the original when you have duplicates or near-duplicates across your site. Without them, you risk splitting ranking signals across multiple URLs. Robots meta tags (noindex, nofollow, or combinations) override your robots.txt file at the page level and are useful for staging environments, filtered pages, or thin content you don't want indexed. Open Graph tags (og:title, og:description, og:image) and Twitter Card markup don't affect Google rankings, but they control how your content appears when shared on social platforms. A clean social preview can drive referral traffic and indirect SEO benefits through increased visibility and backlinks. Skip outdated tags like meta keywords, which Google has ignored since 2009, and avoid keyword stuffing in any meta field. At Ottawa SEO, we automate title and description templates in WordPress or Shopify to ensure consistency across large sites, then manually refine high-traffic pages. For local businesses, we often include the city name in title tags when targeting geographic searches, but only when it reads naturally. Schema markup, while technically not a meta tag, belongs in your head section and can trigger rich snippets that improve CTR. Most CMS platforms and plugins handle viewport and basic tags automatically, so your real work is crafting unique, compelling titles and descriptions for pages that matter.