This unofficial Google SEO checklist definitely accounts for MUCH of the work SEO companies do for onsite and offsite SEO work! Please check out this infographic as it gives you an overview of all the standards in one convenient place! Special thanks to the The Sherwood Group as I stumbled on this via Linkedin! BIG thanks to Single Grain and Backlinko for putting this together with their knowledge!!!!
This infographic includes Google’s ranking properties, domain and backlink factors, plus many more that you can use to help increase your website ranking. Though Google is constantly changing its algorithms this list should serve you well for the time being. You may want to keep it for future reference too!