Start with access and indexability. Important pages need stable URLs, meaningful HTML, a logical internal-link structure and no accidental blocks from robots rules, noindex tags or broken canonicals.
Then review the user journey. Slow templates, layout shifts, confusing navigation and forms that fail on mobile cost both visibility and enquiries. Audit representative service, blog, location and conversion pages rather than judging the site only by its homepage.
Finally, turn findings into a roadmap. Prioritise issues by business impact and effort, fix the most important ones, then measure changes in Search Console, analytics and lead quality.
What to do next
Choose the one improvement most likely to reduce friction for a valuable user journey. Measure the result, learn from it and build from there.