Start with real-user data where possible, then use Lighthouse for repeatable diagnostics. Optimize the largest visible media, preload only critical assets, reduce render-blocking CSS, and delay non-essential JavaScript. Reserve dimensions for images and embeds to prevent layout shifts. Audit plugins for duplicated libraries and expensive frontend behavior. Performance work should be tested across templates, devices and logged-out states, not only on the homepage.
Key takeaway
Build for maintainability, performance and the people who will manage the website after launch.