I've been working in SEO professionally for more than 10 years now with the last 4 years being at agencies. Here is the one-pager that I share with freelancers.
Individual content
Target Keyword 🎯
Each piece of content should include the target KW in the post's title, preferably at the beginning of the title. If you can, fit two KWs in the title, with the primary KW at the beginning of the title.
The target keyword should be mentioned early in the article, preferably in the first sentence of the page.
The target KW and semantically related keywords should be naturally mentioned throughout the content
If possible, the target keyword should be mentioned in one of the subheads. Preferably the H1 and one H2.
Include Local SEO keywords if the post warrants it.
The URL should be as short as possible while containing the target keyword.
Linking
Link internally to other pages on the website whenever possible. Include 3-5+ internal links in each piece of content. Link to internal pages with KW-optimized anchor text.
Never link to another page with the target KW that you want the current page to rank for.
There can be 1-2 external links to influential, authoritative non-competitor sites. The anchor text on these links should not be KW-optimized.
A quick way to find pages to link internally is to search in Google.
site:example.com keyword
Readability
The content should be easy to read in short paragraphs and contain subheads to break up the text.
Multimedia
Try to include 3-4 images from our stock image account
Vouch