Website Optimisation

Improves a site's speed, technical health, usability, and content effectiveness so it performs better for users and search engines alike.

If you treat website optimisation as only speed work, you ignore crawlability, content quality, and mobile usability issues that often matter more.

Key points

Start with a baseline audit – it reveals broken links, slow pages, and mobile usability issues.
Reduce file sizes for HTML, CSS, JavaScript, images, and fonts to improve load times.
Use caching headers and a CDN to improve repeat visits and geographic performance.
Optimise images with WebP or AVIF, responsive sizes, and lazy loading.
Fix technical SEO issues like canonical tags, 301 redirects, and sitemap submission.
Measure with hypotheses and experiments, not by changing many variables at once.

At a glance

Also called: Web performance optimisation, SEO site optimisation
Applies to: All websites, especially content-heavy and e-commerce pages
Controlled by: Web developers, SEO specialists, site owners
Common mixup: Confusing website optimisation with only page speed optimisation
Measured in: Core Web Vitals, page load time, crawl errors, conversion rate

The same site, two different approaches

A news site changed all images to WebP, minified CSS, and added async scripts in one week. Page speed improved by 20%, but organic traffic fell because new mobile layout issues confused users. A slower, measured approach would have isolated the cause. The team later reverted to a controlled test, fixing mobile usability first, then observing a 5% traffic gain.

Four common mistakes in website optimisation

Treating it as only speed work Ignoring crawlability, content quality, and mobile usability means you miss the biggest ranking factors. A fast page that is hard to use or not indexed will not perform.
Changing too many elements at once You cannot tell which change improved performance. Run experiments with one variable at a time, and use monitoring tools to isolate effects.
Over‑optimising assets blindly Reducing image sizes or minifying code is useless if third‑party scripts or render‑blocking resources still create bottlenecks. Check the full waterfall.
Ignoring duplicate URLs and redirects Duplicate pages without canonical tags or with 302 redirects dilute indexing signals. Use 301 redirects for moved pages and canonical tags for similar content.

Three things to measure before you optimise

Baseline technical seo audit A technical seo audit reveals broken links, crawl errors, and mobile issues. Use Google Search Console and a crawl tool to get a complete picture.
Core Web Vitals and real‑user metrics Core Web Vitals give you a baseline for speed and interactivity. Measure LCP, INP, and CLS from real users, not just lab data.
Current content quality and internal linking Thin, outdated content with weak internal links underperforms regardless of speed. Evaluate relevance, authority, and link structure before making changes.

Three areas that often get overlooked

Mobile seo and responsive design Mobile seo is not optional. Ensure touch targets are large, text is readable without zoom, and content is fully accessible on small screens.
Canonical tag and redirect hygiene Set canonical tags correctly to avoid duplicate content signals. Replace broken redirect chains with clean 301 redirects to preserve link equity.
Content quality and freshness Even with perfect speed, thin or outdated content will not rank. Regularly update high‑value pages and strengthen internal linking to support site performance.

Common questions

What is the first step in website optimisation?

Run a baseline audit using tools like Google Search Console and PageSpeed Insights to identify speed, crawl, and mobile issues.

What are the most important metrics for website optimisation?

Core Web Vitals, page load time, crawl error rate, and mobile usability. Monitor these with real‑user data.

How do you optimise a website for mobile?

Use responsive design, optimise images, ensure touch targets are large, and test with Google's mobile‑friendly tool.

Sources

Google Search Central Official guidance on crawlability, indexation, and technical SEO best practices.
Google PageSpeed Insights / Lighthouse Speed and Core Web Vitals reports for any URL with optimisation suggestions.
Google Core Web Vitals Defines LCP, INP, and CLS, and explains how to measure and improve them.
Google Search Console Help Tools for monitoring crawl errors, mobile usability, and index coverage.