Page Title - Not to exceed more than 65 characters.
Meta Description - Not to exceed more than 160 characters.
Meta Keywords - Google Does Not accept meta keywords any more.
Keywords Test - There is likely no optimal keyword density (search engine algorithms have evolved beyond keyword density metrics as a significant ranking factor). It can be useful, however, to note which keywords appear most often in your page, and if they reflect the intended topic of your page. More importantly, the keywords in your page should appear within natural sounding and grammatically.
<h1> - Page should contain one H1 heading. Their contents are listed below:
<h2> - Page should contain at least one H2 headings.
Robots.txt - Your site should use a "robots.txt" file: example http://yourwebsite.com/robots.txt
Sitemap - Place a sitemap on your website: example http://yourwebsite.com/sitemap.xml
Broken Links - Test your website for broken links.
Underscores - Do not use underscores in your in-page URLs!
Image Alt Test - Make sure all images have the required 'alt' attribute.
Inline CSS - Do not use any inline CSS styles.
Favicon - Your website should have a favicon.
Deprecated HTML Tags - Do not use HTML deprecated tags.
Noindex Tag - suggests to search engines (most notably Google) not to index a specific webpage.
Nofollow Tag - suggests to search engines (most notably Google) not to pass link equity through links on a webpage.
Domain Authority - It is good to have domain authority.
Page Authority - It is good to have page authority also.
WWW redirection - A redirect is in place to redirect traffic from your non-preferred domain. your website directs www.yourwebsite.com and website.com to the same URL.
HTML Page Size - Keep your HTML average web page size under 33 Kb.
This leads to a faster page loading time than average.
HTML Compression/GZIP - Use gzip compression on your code. This helps ensure a faster loading web page and improves user experience.
If you follow the above information you will most likely succeed in improving your Google ranking and search engine placement. If you require assistance with any part or all of the above give me a call.