Here is one of the checklists built from my experience and tested on hundreds of sites. This is ordered with the most important at the top.
- Are there inbound links using keywords as anchor text?
- Does the Title Element (tag) start with the desired keyphrase for the page?
- Does the domain name contain the keyphrase?(*requires backlinks to use this keyphrase as the anchor text)
- Does each page (or product) have just one URL on the site?
- Is there a Heading Level 1 (H1) containing the main keyphrase?
- Does the first sentence contain the main keyphrase?
- Does the pathname (directory) contain the keyphrase?
- Does the filename contain the keyphrase?
- Are the desired keyphrases proximate to one another?
- Are other keyphrases towards the beginning of sentences?
- Are important keyphrases in italics or bold?
- Are other keyphrases present in the body text (not at beginning of sentences)?
- Where an image is used as a link, are Alt tags present?
- Does the meta Description tag contain the main keyphrase?
- Do the pages have a theme pyramid-like hierarchy?
- # Are links to the home page coded correctly?
- Does the meta Keywords tag contain the main keyphrase first, followed by others?
- Are there keyphrases in the last para of the page?
- Are there outbound links to major authority sites?
One caution is not to try and do all of this on a single page.