How do I improve my website's loading speed?

Start with measurement. Run Lighthouse (Chrome DevTools → Lighthouse tab) and note your LCP (Largest Contentful Paint), CLS (Cumulative Layout Shift), and INP (Interaction to Next Paint). These are Google's Core Web Vitals and they directly affect your search ranking.

The highest-impact optimizations, in order: 1) Image optimization — convert to WebP/AVIF, set explicit width/height, lazy-load below-the-fold images. This alone can cut LCP by 40-60%. 2) Font loading — self-host fonts, use font-display: swap or optional, preload the primary font file. 3) JavaScript reduction — audit your bundle size, remove unused dependencies, defer non-critical scripts. 4) Caching — set proper Cache-Control headers, use a CDN (Vercel, Cloudflare, Fastly). 5) Server response time — if TTFB exceeds 500ms, consider static generation or edge computing.

Common mistakes: using Google Fonts CDN instead of self-hosting (adds a DNS lookup + connection), loading analytics libraries synchronously, not specifying image dimensions (causes CLS), and using client-side rendering for content that could be server-rendered.

Target metrics: LCP < 2.5s (good), < 1.5s (excellent). CLS < 0.1. INP < 200ms (good), < 100ms (excellent).