According to me, the 3 most important elements in SEO site audit are:
- Backlinks ? Quality & Relevance of backlink (if the website is old) is very important to audit first.
- Technical Analysis: Search engine friendly structure, website speed and various other important factors in technical audit is mandatory in SEO site audit.
- Content & User experience: Unique, relevant and precise content along with better user experience (that can be understood by analyzing bounce rate of the pages) is very important in SEO site audit.