How to Improve Website Speed and Mobile Performance for a New Website

Most new websites load acceptably fast on a desktop with a good connection. The real test is mobile — and that is where many sites quietly fail. Visitors on phones get slower networks, smaller CPU resources, and less patience. If your site has never been optimised for performance, the gap between how it looks in development and how it behaves in the real world can be significant.

The good news is that most performance problems come from a short list of causes and follow a predictable fix process. You do not need to be a developer to address them. The settings, tools, and adjustments in this guide are accessible to anyone managing their own website.

Quick Answer

To improve website speed and mobile performance: enable caching, compress and serve images in modern formats, minify CSS and JavaScript, remove unused plugins or apps, and use a CDN. On WordPress, LiteSpeed Cache handles most of this automatically if your host runs LiteSpeed servers. On other hosts or platforms, a combination of a caching tool and image optimisation will cover the majority of gains.

Why Websites Slow Down

Most websites today are built on a system that assembles each page dynamically — querying a database, processing server-side code, and building the HTML before it reaches the browser. WordPress works this way, as do most other content management systems; a hosted website builder or a static site handles this differently, but the same weight-related causes below still apply either way. That dynamic-building process adds time, especially on shared or under-resourced hosting.

On top of that, themes or templates and plugins or apps load their own stylesheets and JavaScript files. A site with ten add-ons can easily be making twenty or thirty additional HTTP requests per page load. Images that were never compressed or resized add further weight. The cumulative effect is a site that feels slow even when individual elements seem fine.

Mobile performance compounds this. Slower network conditions and less powerful processors mean that every unnecessary byte costs more time on a phone than on a desktop.

Step-by-Step: Improving Website Speed

Work through these steps in order. The early steps deliver the most impact and the later steps refine what remains.

1. Install a caching tool. Caching saves a static copy of your pages so the server does not need to rebuild them from the database on every visit. On WordPress, if your host uses LiteSpeed servers, install LiteSpeed Cache — it integrates directly with the server and is one of the most effective options available; WP Super Cache or W3 Total Cache are reliable alternatives on other hosts. Most other platforms and hosted builders include a caching layer by default, or offer one as a setting — check your host or platform’s performance settings if you’re not on WordPress. Enable page caching first, then explore additional options.
2. Optimise and compress images. Images are typically the largest contributor to page weight, regardless of platform. Compress all uploaded images before or after upload, and serve them in modern formats such as WebP or AVIF where supported. On WordPress, the Performance Lab plugin from the WordPress Performance Team includes a Modern Image Formats module that handles format conversion automatically during upload; most other platforms and image hosts offer an equivalent automatic conversion option.
3. Minify CSS and JavaScript. Minification removes whitespace and comments from code files, reducing their size. Most caching tools and many hosting platforms include a minification option — enable it after caching is working. Test your site after enabling minification, as aggressive settings can occasionally break scripts.
4. Remove unused plugins, themes, or apps. Every active add-on adds potential load time. Deactivate and delete anything you are not using. On WordPress specifically, inactive plugins still occupy disk space and can slow down the admin area even if they do not directly affect the front end — delete unused themes too, leaving only your active theme and one fallback.
5. Enable lazy loading for images. Lazy loading delays the loading of images that are not yet visible in the viewport. This is now standard on most modern platforms — WordPress has included native lazy loading since version 5.5, applied to images automatically. Check that your theme or template is not overriding this behaviour.
6. Reduce database overhead, if your platform has one. WordPress and most other content management systems store post revisions, transients, spam comments, and other data that accumulates over time. On WordPress, use a tool such as the database optimisation feature in LiteSpeed Cache or a dedicated plugin like WP-Optimize to clean up periodically — see the guide on cleaning up and optimising your website’s database for a full walkthrough. This reduces query time, which improves Time to First Byte. Hosted builders and static sites generally don’t carry this overhead at all.
7. Use a CDN for static assets. A Content Delivery Network serves images, CSS, and JavaScript from servers located close to each visitor, reducing delivery time regardless of where your hosting is based or which platform you’re on. This is especially effective for sites with visitors in multiple countries. See the guide on setting up a CDN for your website for a full walkthrough — most platforms offer this as a built-in or one-click option.

Practical Tips for Mobile Performance

Mobile-specific performance goes beyond general speed improvements. A few areas to check specifically:

• Responsive images. Most modern platforms, including WordPress, generate multiple image sizes on upload and serve the appropriate size for the device automatically. Check that your theme or template is using the srcset attribute correctly. On WordPress, the Image Prioritizer module in Performance Lab helps ensure the correct image size loads first above the fold.
• Font loading. Fonts loaded via an external request add DNS lookup time. Either host fonts locally or preconnect to the font provider’s domain. On WordPress, LiteSpeed Cache has a Google Fonts option that can localise them automatically — check whether your platform or caching tool offers an equivalent.
• Eliminate render-blocking resources. JavaScript files loaded in the <head> delay rendering. Most caching tools can defer or async load scripts. Enable this setting carefully and test after each change — some scripts need to load in order.
• Avoid redirects. Every redirect adds a round trip. Make sure www and non-www versions of your domain resolve to the same place without chaining multiple redirects. On WordPress, check that your WordPress Address and Site Address in Settings → General match your actual domain; other platforms have an equivalent site-URL setting worth double-checking.

Common Mistakes

• Enabling too many caching options at once. Caching tools have many settings. Turn on page caching first, confirm it works, then enable minification and other options one at a time. If something breaks, you will know exactly what caused it.
• Not testing on mobile after changes. Desktop performance and mobile performance are not always correlated. After any significant change, test on a real phone or use the mobile simulation in Chrome DevTools.
• Using a heavy page builder without considering the cost. Page builders add substantial JavaScript and CSS to every page. If you are building a new site and performance is a priority, choose a lightweight builder or build with your platform’s native editor directly.
• Ignoring hosting quality. No amount of optimisation fully compensates for underpowered hosting. If your server response time (TTFB) is consistently above 600ms, consider upgrading your plan or switching hosts before investing more time in plugin-level fixes.

Measuring the Results

After making changes, measure the impact rather than estimating it. Google PageSpeed Insights gives you a structured breakdown of what is still affecting your score and what has improved. Run it on both mobile and desktop views — the scores and recommendations often differ between the two.

Focus on the Core Web Vitals section: Largest Contentful Paint (LCP), Cumulative Layout Shift (CLS), and Interaction to Next Paint (INP). These are the metrics Google uses in ranking signals. Improving them tends to have the most practical benefit beyond just faster load times.

One technique that sits underneath all of this is lazy loading — deferring the loading of offscreen images and iframes until they’re actually needed. Most platforms enable this natively, but it’s worth understanding how to verify it’s working and how to extend it through your caching tool.

If you want to go further with caching specifically, enabling browser caching for your website is one of the most effective next steps — it tells returning visitors’ browsers to store static files locally, reducing load time on every page after the first.

For more on this, see our guide on Do Competitor Research for a New Website.

Plugin count is one of the most overlooked factors here — a site can be otherwise well optimised and still feel sluggish because of a handful of heavy, rarely-used plugins running on every page. If your speed hasn’t improved as much as expected after the steps above, see our guide on how to reduce plugin bloat for better site performance for a walkthrough on finding and removing the specific plugins slowing you down.

Conclusion

Set up caching suited to your platform, compress your images and serve them in modern formats, and remove plugins or apps you are not using. Those three steps alone will address the majority of website performance problems. Measure with PageSpeed Insights before and after so you can see clearly what changed.