Before you start
Crawl the site and export every URL, including posts and PDFs
Export pages with clicks and impressions from Search Console
Note the pages that bring in enquiries
Record each page's title, meta description and H1
Check which pages other sites link to
During the build
Keep the URLs that rank wherever you can
Map every old URL to its closest new page
Carry over or improve the content that ranks
Write a unique title and description for every page
Build on a staging site that search engines can't index
At launch
Set up 301 redirects for every URL that changes
Make sure the live site isn't blocking search engines
Submit the new XML sitemap in Search Console
Test forms, analytics and conversion tracking
After launch
Check redirects for errors and chains
Watch Search Console for crawl errors and dropped pages
Compare rankings and traffic with your baseline