Recently a friend of mine, a seasoned web programmer, shares his criteria to the quality website. Here are they listed.
- speed of loading
- mobile friendliness
- unique metas and H tags for each page
- correct schema data
- favicons for different gadgets
- optimized images
- internal linking
- robots txt + sitemap xml
- google analytics counter (or/and yandex metrika)
- retargeting pixels for FB and VK (VKontakte)
The half of listed points are related to Technical audit, some to SEO optimization (unique metas and H tags, internal linking). I would emphasize SEO-related points make sense only in regard of the target keywords. Thus one should publish a website prior to collecting the target keywords with traffic stats and map them against the website structure.