Images, fonts, animation and third-party scripts all affect loading and interaction. The first step in improving Core Web Vitals is not to start changing things, but to find the real bottleneck.
What the three metrics measure
Largest Contentful Paint (LCP): how long the main content takes to appear, usually decided by the hero image or heading block.
Cumulative Layout Shift (CLS): whether the layout jumps while loading, often caused by unsized images, ads or font swapping.
Interaction to Next Paint (INP): how quickly the interface responds to a tap or click, which relates to unnecessary JavaScript.
Measure representative live pages
Do not test only an empty page or the homepage. Review the homepage, service pages and news templates separately, because their layouts and components differ.
Compare field data with lab data: field data reflects real visitor experience, while lab data makes specific fixes easier to locate.
Remove obvious waste first
Compress above-the-fold images and use modern formats at correct dimensions. The hero image is often the LCP element.
Avoid loading duplicate font files and keep only the weights actually used. Font files are heavy and delay text rendering.
Defer non-essential third-party scripts such as chat widgets, tracking tags and social embeds so primary content appears first.
Reserve dimensions for images and blocks to reduce layout movement.
A common misunderstanding
A performance score is not a ranking guarantee. It is an experience signal, while results still depend mainly on content quality, relevance and overall site credibility. Moving a score from red to green is worth doing, but not at the cost of function or content.
Verify after every change
Retest after each change to protect visual quality and functionality. Change one category at a time so you can tell what produced the effect.
If speed and content compete for budget, read Five priorities for business websites in the 2026 search environment first, then decide the order of work.
In our optimisation projects we measure representative pages, rank the fixes with expected impact, then implement and recheck each one.