Do it directly:
- Run Lighthouse and note the score
- Check what's slowing things down: large images? Too much code? Slow font loading?
- Optimize: image compression, lazy loading, font preloading
- Run Lighthouse again
Tell the user: "Optimization is done. The homepage used to take X seconds to load, now it only takes Y seconds. I mainly did three things: compressed the images without affecting quality, made non-urgent code load only when needed, and prepared the fonts in advance. The Lighthouse score went from X to Y."