Search Engine Optimization (SEO)

A helpful checklist / collection of Search Engine Optimization (SEO) tips and techniques.

Contents

• URL
• Accessibility
• Meta Information
• Keywords
• Content
• Images
• Videos
• Links
• Mobile
• Sitemap
• Social Media
• Tools & Services
  • Webmasters
  • Analytics
  • Optimization
  • Keywords
  • Links
  • Structured Data
  • Bookmarklets
  • Browser Extensions
  • Jekyll Plugins
  • TYPO3 Extensions
  • WordPress Plugins
• Books
• Courses

URL

• Descriptive URLs: Use a descriptive page url, which should reflect your targeted keyword.
• File extension - Do not strip out the file extension on URLs.
• HTTPS - Security is a top priority for Google.
• Hyphens - Split words using hyphens.
• Localisation - Choose a country-specific domain, for better local search results.
• Subdomain or subfolder - Subdomains are seen as separate domains.
• URL builder - Use this tool to add custom campaign parameters to your URLs.

Accessibility

• 403: Provide a 403 - Access denied page.
• 404: Provide a 404 - Page not found page.
• Custom Search - With Google Sitelink search box, people can reach your content more quickly.
• File not found: Avoid 404 FILE_NOT_FOUND errors.
• Layout: Use divs instead of tables for layout. Using tables is not semantically correct.
• Moving a website: Redirect all your links to the new location via .htaccess.
• Pagination - Implement the rel="next" and rel="prev" attributes to links.
• Performance - Performance and loading time is important.
• Redirects: Avoid redirects if possible. Use 301 redirect instead of 302.
• RichSnippets - Markup your code with rich snippets, they show up on the search results page.
• Robots - Block pages which should not be indexed via the robots.txt file or <meta name="robots" content="">.
• Validation: Write valid code (HTML Validator CSS Validator).
• WAI-Aria - Use WAI-Aria tags to help machines understand your code.

Meta Information

• Description - Each page should have a unique description (max. 160 characters) <meta name="description" content="">.
• Title: Each page should have a unique speaking title (60 - 100 characters) <title>Website Title</title>.

Keywords

• Content: Keyword should appear in ~3% of article length.
• Heading: Keyword should appear in headings.
• Meta Tag - You can ommit the <meta name="keywords" content="">, search engines do not use this meta tag.
• Research: Rank for keywords with high traffic and less competition.
• Single: Every page should have a single unique targeted keyword.
• Title: Keyword should appear in page title.
• URL - Keyword should appear in URL name.

Content

• Content: Content matters the most in SEO.
• Flash: Avoid Flash content and Flash pages. They are not accessible on mobile phones and will be ranked lower.
• Freshness: New content is important. Updating pages or posting regularly is recommended.
• Headings: Clear structure H1 -H6 max. 70 characters long.
• Length: Article should be at least 300 words.
• Strong: Use strong tag to highlight your targeted keyword.
• Uniqueness - Do not provide duplicated content, use unique content types.

Images

• Alt tag - Add an alt-tag this a description of the image (60 - 70 characters).
• Dimensions: Add the width="" and height="" attributes to the image.
• File name - Use a short descriptive name.
• Optimization - Optimize images by removing some meta information.
• Responsive Images - Serve the most optimized image corresponding to the window size.
• Size: keep the filesize as low as possible.

Videos

• Controls: Add controls to playback and control your video.
• Embed: Allow others to embed your videos.
• Transcriptions: Use transcriptions for indexing, usability & content.
• Unplayable content - Avoid unplayable video content. Use HTML5 <video> tag instead of Flash.

Links

• Backlinks: Only add external links if you got a backlink to your site.
• Internal links: Add ~3 internal links to your content.
• Languages - The hreflang tag tells Google which language you are using on a specific page, so the search engine can serve that result to users searching in that language <link rel="alternate" href="example.com/fr/" hreflang="fr-fr" />.
• Naming: Use a descriptive link name: “Click here” or “Read more” are bad link text. Better “Read more about SEO and Web Accessibility”.
• nofollow - Add rel="nofollow" attribute to external links only to prevent spam and bad links.
• Title: add the title attribute to links.

Mobile

• AppLinks - Apps that link to your content can then use this metadata to deep-link into your app.
• mobile friendly - Mobile optimized sites are marked in search results. Test for mobile friendly site.
• Smart App Banner - Safari has a Smart App Banner feature that provides a standardized method of promoting apps on the App Store from a website.
• Tap targets - Clickable links should not be too small.
• Viewport: Tell browsers how to adjust the page's dimensions and scaling to suit the device <meta name="viewport" content="width=device-width, initial-scale=1">

Sitemap

• HTML sitemap - A HTML sitemap allows site visitors to easily navigate a website.
• Image sitemap - Increase that your images can be found in Image Search results.
• Mobile sitemap - For feature phones, you can create a mobile sitemap.
• Video sitemap - Make sure, search engines know about all the video content on your site.
• XML sitemap - Help search engines to index your pages.

Social Media

• Authorship information.
• Facebook - Sharing Best Practices for Websites & Mobile Apps.
• OpenGraph - The Open Graph protocol enables any web page to become a rich object in a social graph.
• Social Profiles - Add social profiles to your Google search results.
• Social Shares: Provide sharing options for your site.
• Twitter - With Twitter cards, you can attach photos, videos and media experience to you Tweets.

Tools & Services

Webmasters

• Bing Webmasters - Allows webmasters to add their websites to the Bing index crawler.
• Google Search Console (GWT) - Allows webmasters to check indexing status and optimize visibility of their websites.
• Google Tag Manager - Learn about Google Analytics Tag Manager and how it can help simplify your life and need for IT requests. Launch new tags with a few clicks.

Analytics

• Ahrefs - Analyze websites, track social media, build backlinks - Ahrefs has you covered. Try our marketing and SEO tools Site Explorer and Content Explorer today!
• BuzzSumo - Find the most shared content for any topic or domain.
• Followerwonk - Tools for Twitter Analytics, Bio Search and More.
• Google Analytics - Generate detailed statistics about a website's traffic.
• Open Site Explorer - Use Open Site Explorer to identify link building opportunities. Research backlinks, identify top pages, view social activity, and analyze anchor text.
• Matomo - An open analytics platform.
• SEMrush - SEMrush is a powerful and versatile competitive intelligence suite for online marketing, from SEO and PPC to social media and video advertising research.
• Seomator - SEO Audit Tool and website crawler for SEO performance improving with How-to-Fix tips.
• SEOstats - SEOstats is a powerful open source PHP library to request a bunch of SEO relevant metrics.
• SimilarWeb - Compare website traffic with SimilarWeb.com's advanced traffic estimator tool. See any website's traffic sources & uncover their online marketing strategies.
• SpyFu - Unlimited searches of any competitor's keywords for SEO or Google Ads. Research keywords, and find any domain's strongest content and their most dominant ad copy.
• Twitter Analytics - Measure and boost your impact on Twitter.
• Plausible - Simple and privacy-friendly alternative to Google Analytics.

Optimization

• Web.dev - Get the web's modern capabilities on your own sites and apps with useful guidance and analysis from Web.dev. Whether you already have a website or you're just getting started, learn to build for the modern web at Web.dev.
• PageSpeed Insights - Page Speed Insights measures the performance of a page for mobile devices and desktop devices.
• Varvy Seo tool - Displays: domain strength, links, image seo, social counts & mentions, page/technical seo, pagespeed and more.
• Webpagetest.org - Web Page Test gives you an overall performance waterfall as well as rendering timeline for sites. It also provides critical insight into time to first byte and what could be holding back web page performance.
• WooRank - WooRank will help you to address issues on your site & identify