Not all technical SEO issues are created equal. This list focuses on the 12 factors our team at 3iseo consistently sees having the most measurable ranking impact — drawn from conducting comprehensive audits across thousands of websites.
1. Largest Contentful Paint (LCP)
LCP measures how quickly the largest visible element loads. A poor LCP (over 4 seconds) is a confirmed negative ranking signal. Target under 2.5 seconds. Fix it by optimising your largest image, improving server response time, and eliminating render-blocking resources.
2. Interaction to Next Paint (INP)
INP replaced FID in March 2024. It measures your page’s responsiveness to all user interactions. A poor INP (over 500ms) signals JavaScript performance issues. Target under 200ms for a “Good” rating.
3. Cumulative Layout Shift (CLS)
CLS measures visual stability. Elements that move as the page loads are penalised. Most CLS issues come from images without defined dimensions, dynamically injected content, and web fonts causing layout shifts on load.
4. Mobile-First Indexing Compliance
Google indexes the mobile version of your site first. If your mobile experience is inferior — slower, with missing content, or broken structured data — you are being ranked on a worse version of your site than the one desktop visitors see.
5. Canonical Tag Implementation
Incorrect or missing canonical tags lead to duplicate content issues — splitting authority across multiple versions of the same page. Every page should have a self-referencing canonical tag.
6. Structured Data (Schema Markup)
Structured data wins rich snippets that dramatically improve click-through rates. Implement LocalBusiness, Product, Article, FAQ, and Review schema where relevant.
7. Internal Linking Architecture
A deliberate internal link structure distributes authority to your most important pages and helps Google understand your site’s topical hierarchy. Orphan pages receive minimal crawl attention and rarely rank. Our on-page SEO service includes a full internal linking audit and rebuild.
8. Crawl Budget Management
For large sites, Google allocates a finite crawl budget. Wasting it on low-value pages means your most important pages get crawled less frequently. A clean robots.txt and accurate XML sitemap are non-negotiable.
9. Site Speed — Server Response Time
Time to First Byte should be under 800ms. Slow TTFB is typically caused by inadequate hosting, unoptimised databases, or absence of server-side caching. Often the single highest-impact quick win in a technical SEO audit.
10. Image Optimisation
Images in modern formats (WebP, AVIF) that are appropriately sized and compressed. Every image needs a descriptive alt attribute. Implement lazy loading for below-the-fold images.
11. Redirect Chain Cleanup
Redirect chains (URL A to URL B to URL C) dilute link equity and slow page loads. Consolidate to single-hop 301 redirects wherever possible.
12. JavaScript Rendering
If your website relies heavily on JavaScript to render content, Google may not be indexing it correctly. Use Google Search Console’s URL Inspection tool to check this regularly.
We recommend a full technical SEO audit every six months. Our free audit covers all 12 factors and delivers a prioritised action plan within 24 hours.
SEO Strategist at 3iseo. Helping businesses see beyond the algorithm since 2010.