There are more factors than just this for On-page SEO, but I feel these are the lowest hanging fruit to work on for each page.
This includes your page’s title and desctiption tags. At the very least the first thing that’s done after a page has been created and content has been added.
Keyword in H1 Tag
There should be a connection between the title tag, the H1 tag and the content of the page.
Proper User of H Tags
Header tags, otherwise known as H tags are an important and technical way of telling Google how your content is structured.
Keyword in URL
This should be a natural item to check off as you should have a one to one connection between the title of the page and that title residing in the URL of that page.
Using Keywords in the Pages Copy/Content
Although Google has moved away from a keyword centric algorithm and now relies on the quality of the content of the page in order to rank (Yes I know, it sounds like a, “Duh” comment), you can’t write about SEO with writing…the word SEO on the page. Make sense?
The Length of the Content
This changes yearly. It’s bounced around from 350 – 650 words to now almost 2,000 words on a page in order to rank well. But, I’ve also seen pages as low as 50 rank well. The take away from this is the higher quality the content, the better change you’re going to rank higher.
This not only covers copying content from another page, (Do not do this. Period.) But also using the same content over and over on your website. Do this and you’ll be the black mark of death by Google (See below on ways to get around this).
What’s a canonical tag? A canonical tag tells search engines that content on this page is referenced somewhere else and that page should be considered the master copy of a page. Using a canonical tag will remove problems with duplicate content and getting red flagged by Google.
Alt and title text, captions, and descriptions should be used so Google can have indicators of what the image is of. Yes, Google cannot tell what an image is…in most cases and algoriths have shown that Google can tell that a picture of a cat is a cat and not a Flerken.
Linking to authoritative pages can send out signals of trust to a search engine, but sending out too many can also work against you (Ever seen a link dump directory?).
Google a few years ago updated their algothrim to put more enphasis on the content of a page rather than just how many keywords reside there. Linking like content to each other within a site builds a tighter content web within a page and builds the strenth between them. It’s what Hubspot calls “Topic Clusters” and is a content strategy I like to work with on websites.