SEO optimization

Search engine optimization based on Lighthouse SEO audits and Google Search guidelines. Focus on technical SEO, on-page optimization, and structured data.

SEO fundamentals

Search ranking factors (approximate influence):

Factor Influence This Skill

Content quality & relevance ~40% Partial (structure)

Backlinks & authority ~25% ✗

Technical SEO ~15% ✓

Page experience (Core Web Vitals) ~10% See Core Web Vitals

On-page SEO ~10% ✓

Technical SEO

Crawlability

robots.txt:

/robots.txt

User-agent: * Allow: /

Block admin/private areas

Disallow: /admin/ Disallow: /api/ Disallow: /private/

Don't block resources needed for rendering

❌ Disallow: /static/

Sitemap: https://example.com/sitemap.xml

Meta robots:

<!-- Default: indexable, followable --> <meta name="robots" content="index, follow" />

<!-- Noindex specific pages --> <meta name="robots" content="noindex, nofollow" />

<!-- Indexable but don't follow links --> <meta name="robots" content="index, nofollow" />

<!-- Control snippets --> <meta name="robots" content="max-snippet:150, max-image-preview:large" />

Canonical URLs:

<!-- Prevent duplicate content issues --> <link rel="canonical" href="https://example.com/page" />

<!-- Self-referencing canonical (recommended) --> <link rel="canonical" href="https://example.com/current-page" />

<!-- For paginated content --> <link rel="canonical" href="https://example.com/products" /> <!-- Or use rel="prev" / rel="next" for explicit pagination -->

XML sitemap

<?xml version="1.0" encoding="UTF-8"?> <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"> <url> <loc>https://example.com/&#x3C;/loc> <lastmod>2024-01-15</lastmod> <changefreq>daily</changefreq> <priority>1.0</priority> </url> <url> <loc>https://example.com/products&#x3C;/loc> <lastmod>2024-01-14</lastmod> <changefreq>weekly</changefreq> <priority>0.8</priority> </url> </urlset>

Sitemap best practices:

• Maximum 50,000 URLs or 50MB per sitemap

• Use sitemap index for larger sites

• Include only canonical, indexable URLs

• Update lastmod when content changes

• Submit to Google Search Console

URL structure

✅ Good URLs: https://example.com/products/blue-widget https://example.com/blog/how-to-use-widgets

❌ Poor URLs: https://example.com/p?id=12345 https://example.com/products/item/category/subcategory/blue-widget-2024-sale-discount

URL guidelines:

• Use hyphens, not underscores

• Lowercase only

• Keep short (< 75 characters)

• Include target keywords naturally

• Avoid parameters when possible

• Use HTTPS always

HTTPS & security

<!-- Ensure all resources use HTTPS --> <img src="https://example.com/image.jpg" />

<!-- Not: --> <img src="http://example.com/image.jpg" />

Security headers for SEO trust signals:

Strict-Transport-Security: max-age=31536000; includeSubDomains X-Content-Type-Options: nosniff X-Frame-Options: DENY

On-page SEO

Title tags

<!-- ❌ Missing or generic --> <title>Page</title> <title>Home</title>

<!-- ✅ Descriptive with primary keyword --> <title>Blue Widgets for Sale | Premium Quality | Example Store</title>

Title tag guidelines:

• 50-60 characters (Google truncates ~60)

• Primary keyword near the beginning

• Unique for every page

• Brand name at end (unless homepage)

• Action-oriented when appropriate

Meta descriptions

<!-- ❌ Missing or duplicate --> <meta name="description" content="" />

<!-- ✅ Compelling and unique --> <meta name="description" content="Shop premium blue widgets with free shipping. 30-day returns. Rated 4.9/5 by 10,000+ customers. Order today and save 20%." />

Meta description guidelines:

• 150-160 characters

• Include primary keyword naturally

• Compelling call-to-action

• Unique for every page

• Matches page content

Heading structure

<!-- ❌ Poor structure --> <h2>Welcome to Our Store</h2> <h4>Products</h4> <h1>Contact Us</h1>

<!-- ✅ Proper hierarchy --> <h1>Blue Widgets - Premium Quality</h1> <h2>Product Features</h2> <h3>Durability</h3> <h3>Design</h3> <h2>Customer Reviews</h2> <h2>Pricing</h2>

Heading guidelines:

• Single <h1> per page (the main topic)

• Logical hierarchy (don't skip levels)

• Include keywords naturally

• Descriptive, not generic

Image SEO

<!-- ❌ Poor image SEO --> <img src="IMG_12345.jpg" />

<!-- ✅ Optimized image --> <img src="blue-widget-product-photo.webp" alt="Blue widget with chrome finish, side view showing control panel" width="800" height="600" loading="lazy" />

Image guidelines:

• Descriptive filenames with keywords

• Alt text describes the image content

• Compressed and properly sized

• WebP/AVIF with fallbacks

• Lazy load below-fold images

Internal linking

<!-- ❌ Non-descriptive --> <a href="/products">Click here</a> <a href="/widgets">Read more</a>

<!-- ✅ Descriptive anchor text --> <a href="/products/blue-widgets">Browse our blue widget collection</a> <a href="/guides/widget-maintenance">Learn how to maintain your widgets</a>

Linking guidelines:

• Descriptive anchor text with keywords

• Link to relevant internal pages

• Reasonable number of links per page

• Fix broken links promptly

• Use breadcrumbs for hierarchy

Structured data (JSON-LD)

Organization

<script type="application/ld+json"> { "@context": "https://schema.org", "@type": "Organization", "name": "Example Company", "url": "https://example.com", "logo": "https://example.com/logo.png", "sameAs": ["https://twitter.com/example", "https://linkedin.com/company/example"], "contactPoint": { "@type": "ContactPoint", "telephone": "+1-555-123-4567", "contactType": "customer service" } } </script>

Article

<script type="application/ld+json"> { "@context": "https://schema.org", "@type": "Article", "headline": "How to Choose the Right Widget", "description": "Complete guide to selecting widgets for your needs.", "image": "https://example.com/article-image.jpg", "author": { "@type": "Person", "name": "Jane Smith", "url": "https://example.com/authors/jane-smith" }, "publisher": { "@type": "Organization", "name": "Example Blog", "logo": { "@type": "ImageObject", "url": "https://example.com/logo.png" } }, "datePublished": "2024-01-15", "dateModified": "2024-01-20" } </script>

Product

<script type="application/ld+json"> { "@context": "https://schema.org", "@type": "Product", "name": "Blue Widget Pro", "image": "https://example.com/blue-widget.jpg", "description": "Premium blue widget with advanced features.", "brand": { "@type": "Brand", "name": "WidgetCo" }, "offers": { "@type": "Offer", "price": "49.99", "priceCurrency": "USD", "availability": "https://schema.org/InStock", "url": "https://example.com/products/blue-widget" }, "aggregateRating": { "@type": "AggregateRating", "ratingValue": "4.8", "reviewCount": "1250" } } </script>

FAQ

<script type="application/ld+json"> { "@context": "https://schema.org", "@type": "FAQPage", "mainEntity": [ { "@type": "Question", "name": "What colors are available?", "acceptedAnswer": { "@type": "Answer", "text": "Our widgets come in blue, red, and green." } }, { "@type": "Question", "name": "What is the warranty?", "acceptedAnswer": { "@type": "Answer", "text": "All widgets include a 2-year warranty." } } ] } </script>

Breadcrumbs

<script type="application/ld+json"> { "@context": "https://schema.org", "@type": "BreadcrumbList", "itemListElement": [ { "@type": "ListItem", "position": 1, "name": "Home", "item": "https://example.com" }, { "@type": "ListItem", "position": 2, "name": "Products", "item": "https://example.com/products" }, { "@type": "ListItem", "position": 3, "name": "Blue Widgets", "item": "https://example.com/products/blue-widgets" } ] } </script>

Validation

Test structured data at:

• Google Rich Results Test

• Schema.org Validator

Mobile SEO

Responsive design

<!-- ❌ Not mobile-friendly --> <meta name="viewport" content="width=1024" />

<!-- ✅ Responsive viewport --> <meta name="viewport" content="width=device-width, initial-scale=1" />

Tap targets

/* ❌ Too small for mobile */ .small-link { padding: 4px; font-size: 12px; }

/* ✅ Adequate tap target */ .mobile-friendly-link { padding: 12px; font-size: 16px; min-height: 48px; min-width: 48px; }

Font sizes

/* ❌ Too small on mobile */ body { font-size: 10px; }

/* ✅ Readable without zooming */ body { font-size: 16px; line-height: 1.5; }

International SEO

Hreflang tags

<!-- For multi-language sites --> <link rel="alternate" hreflang="en" href="https://example.com/page" /> <link rel="alternate" hreflang="es" href="https://example.com/es/page" /> <link rel="alternate" hreflang="fr" href="https://example.com/fr/page" /> <link rel="alternate" hreflang="x-default" href="https://example.com/page" />

Language declaration

<html lang="en"> <!-- or --> <html lang="es-MX"></html> </html>

SEO audit checklist

Critical

• HTTPS enabled

• robots.txt allows crawling

• No noindex on important pages

• Title tags present and unique

• Single <h1> per page

High priority

• Meta descriptions present

• Sitemap submitted

• Canonical URLs set

• Mobile-responsive

• Core Web Vitals passing

Medium priority

• Structured data implemented

• Internal linking strategy

• Image alt text

• Descriptive URLs

• Breadcrumb navigation

Ongoing

• Fix crawl errors in Search Console

• Update sitemap when content changes

• Monitor ranking changes

• Check for broken links

• Review Search Console insights

Tools

Tool Use

Google Search Console Monitor indexing, fix issues

Google PageSpeed Insights Performance + Core Web Vitals

Rich Results Test Validate structured data

Lighthouse Full SEO audit

Screaming Frog Crawl analysis

References

• Google Search Central

• Schema.org

• Core Web Vitals

• Web Quality Audit