What the head of a page controls
The title tag and meta description are the main material Google uses for the title link and snippet on its results page, although Google may rewrite either one. Open Graph tags control the preview card when someone shares your link on Facebook, LinkedIn, Slack or WhatsApp, and X reads its own twitter:card tag plus your Open Graph values. The canonical tag tells search engines which URL is the main version of a page, and the robots meta tag can keep a page out of the index.
Writing titles and descriptions that get clicks
Put the main topic of the page near the start of the title and keep it to roughly 50-60 characters, since Google cuts titles by pixel width. Make the description a specific, honest summary of what the reader will get, around 140-160 characters. Every page should have its own title and description; duplicates across many pages make it harder for Google and for searchers to tell the pages apart. The meta keywords tag is ignored by Google, so there's no need to add it.
Canonical tags and duplicate pages
When the same content is reachable at several URLs, for example with and without tracking parameters, or on both http and https, search engines have to pick one version to index. A canonical tag on each copy pointing to the main URL tells them which one you prefer. Google treats it as a strong hint rather than a command, and it can choose differently if other signals, such as your internal links and sitemap, point somewhere else. Keep those signals consistent: link internally to the canonical URL and list only canonical URLs in your sitemap.
Social previews: Open Graph and X cards
A share card needs three things: a title, a short description and an image. For og:image, 1200 by 630 pixels is the commonly recommended size, and an image with little or no small text reads best at thumbnail size. Platforms cache previews, so after you change your tags, run the URL through the platform's own debugger to make it fetch the page again; otherwise people may keep seeing the old card for a while.
What structured data does, and what it doesn't
Structured data, usually written as JSON-LD with the Schema.org vocabulary, describes the facts on a page in a form machines can read: the headline and author of an article, the price of a product, the address of a business. It can make a page eligible for rich results such as product prices and ratings, but it doesn't guarantee them and it isn't a ranking factor on its own. The markup must match what visitors can see on the page.
What changed for rich results
In August 2023 Google limited FAQ rich results to well-known, authoritative government and health websites and removed HowTo rich results altogether. Google also doesn't show review stars for LocalBusiness or Organization markup when a business publishes reviews about itself. Many older tutorials still promise these features, so check the date of any guide before you follow it. Product, Article, Breadcrumb and Event markup all still have Google features where they apply.
Checking your work
Preview link cards with the Facebook Sharing Debugger or LinkedIn Post Inspector before you share a page widely. Test structured data with Google's Rich Results Test, which shows Google-specific eligibility, and validator.schema.org, which checks the markup against the full vocabulary. After publishing, Search Console reports structured data errors across your whole site.