Core Web Vitals reward sites that load quickly, stay stable while loading, and respond fast to input. Here is the checklist I actually work through on WordPress, roughly in order of impact.
Largest Contentful Paint (LCP)
Serve a fast hosting stack, add page caching, and put a CDN in front of static assets. Optimise the hero image — right dimensions, modern format (WebP/AVIF), and preloaded so it is not discovered late. Self-host fonts and preload the ones used above the fold.
Cumulative Layout Shift (CLS)
Give every image and embed explicit width and height so the browser reserves space. Reserve space for ad slots and late-loading widgets, and avoid injecting banners above existing content.
Interaction to Next Paint (INP)
Trim third-party scripts, defer what is not needed for the first interaction, and break up long JavaScript tasks. On WordPress that often means auditing plugins and removing anything that loads globally but is only needed on one page.
Measure, do not guess
Always test on real pages with field data (Search Console / CrUX) alongside lab tools like Lighthouse. Fix, re-measure, and confirm the gains held before moving on.