Measure what visitors experience
Core Web Vitals cover loading, responsiveness, and layout stability. Google’s good thresholds are LCP at 2.5 seconds or less, INP at 200 milliseconds or less, and CLS at 0.1 or less, assessed at the 75th percentile of visits. These are useful experience targets, not a promise of first-place search rankings. A fast laboratory run also cannot describe every real visitor’s connection and device.
Give media a deliberate place
Reserve space for images and video before they load so nearby text does not jump. Use appropriately sized images and a lightweight video poster. Decide whether a video needs to load immediately or can wait until it approaches the viewport. If the footage includes readable text, choose a framing that preserves it on a narrow screen rather than cropping it to fill an arbitrary shape.
Make interaction the priority
A visitor should be able to tap navigation or submit a form while decorative effects are running. Reduce unnecessary work during scroll, avoid loading every preview at once, and pause media that is no longer visible. Give sound a clear control and respect reduced-motion preferences. Animation should support the task instead of holding the visitor in place.
Test beyond the homepage
Check a project page, a long article, and the contact flow as well as the first screen. Compare mobile and desktop results, then use real-user data when it is available to understand recurring issues. Work on the largest bottleneck first and measure again after the change. Keep a short record of what improved so the next visual update does not quietly undo it.