Fast websites are usually the result of many small decisions rather than one large optimization. Start with the parts users feel first: document weight, images, JavaScript, database queries and server response time.
Keep the first request simple
Render useful HTML on the server, defer non-critical scripts and avoid loading libraries that are not needed on the current page.
Optimize images before adding complexity
- Resize images to realistic display dimensions.
- Prefer modern formats when practical.
- Use lazy loading below the fold.
- Set image width and height to reduce layout movement.
Measure database work
Fetch only the fields you need and add indexes for common filters and joins.
Performance is easiest to preserve when it is treated as a feature from the first phase.