Structure before surface
The hardest part of a website is deciding what goes first, what goes next, and what does not go on the page at all. We do that before any visual work, because a page that says the right things in the wrong order cannot be rescued with typography.
That work produces something you can argue with: an outline of every page, what it claims, and what it asks the visitor to do next. Disagreements are much cheaper at that stage than at the mockup.