Start with a page that matters, such as your service page or booking form. Load it on a phone over mobile data. Notice what takes longest to appear and whether a button moves just as you tap it. Run PageSpeed Insights on the same URL for clues about the cause.
Check the largest thing on screen
The first large image often takes up much of the download. Serve a size close to what the phone displays and reserve its space in the layout. Keep that first visible image available immediately. Save lazy loading for images farther down the page.
Review scripts one at a time
Chat, maps, tracking and scheduling tools all compete for the phone’s attention. Keep the tools the page needs, and check whether the rest can wait until a visitor asks for them. Re-run the same test after each change and try the booking or enquiry flow again. That last check keeps a faster score from hiding a broken feature.
Follow one customer task from start to finish
A restaurant menu can open quickly, then stall when a customer taps the ordering link. In that case, re-encoding the homepage photos may improve one measurement while leaving the ordering problem in place. Test a complete task with a cold browser and keep the page addresses in your notes. Look for the longest wait the customer actually experiences.
- Open the landing page over a mobile connection and watch how long the main text and first action take to become usable.
- Follow the booking or ordering link and note whether the wait starts before or after leaving your domain.
- Make one change, test the same path again, and check that the site still works with keyboard input and enlarged text.
Make fast pages easier to maintain
Give the next person who uploads a photo an example of a good source image and expected crop. Record which tools load across the whole site and which belong on one page. For instance, an interactive map may be valuable on the directions page while adding weight to every other page. Keep the address and a directions link available independently of the map. Then repeat the baseline check after the next tool or template changes.