Performance work starts with profiling representative templates and devices. A homepage score alone can hide slow product pages or interaction delays introduced by third-party code.
Images and video need correct dimensions, responsive formats and restrained loading. Theme code should ship only what the current template needs, while apps should be reviewed for duplicated functionality.
Treat performance as an operating discipline. New campaign scripts, app installs and content can reverse a one-time clean-up unless ownership and checks are documented.
Choose one high-value journey, document the current evidence and give the next change an owner, a success signal and a review date.