Avoid "dangling links", these are web pages other pages link to, but that have no outbound links. Google's PageRank algorithm looks for pages with dangling links and assigns them a PageRank of 0.
All web pages should have a HTML hypertext link to the site's home page, this avoids the dangling link problem and passes a portion of each web page's PageRank back to the site's home page.
Ensure the site has a Site Map webpage to make it easy for web crawlers to fully index a website by providing a standard HTML hypertext link on the homepage to the Site Map page.
On the site map page, create a list of standard HTML hyperlinks to every web page contained in the website. If a website has multiple optimised pages, it is probable that a web spider will not always access the site through the website's home page. With a link on every page back to the home page, and a link from the home page to a sitemap it is ensured that after downloading the site map page, all other pages in the web site will be visible and easily found making indexing simple.
Always attempt to ensure all pages contain an adequate amount of interesting, on topic, relevant and original text displaying the sites specialist knowledge.
Avoid duplicating text that can be found on any other web page. Some search engines only index the first 200 words of text, so use this as a guide to the minimum amount of text on each page.
Mobile friendly pagesBe aware that if your pages are not 'mobile friendly', which really means optimised to render correctly on mobile phones, Google may lower the ranking the pages currently have in favour of pages that are optimised for mobile. It is increasingly important that your site and any new content is created with this in mind. To ensure your pages pass the Google mobile friendly test there is a tool here to test your pages are mobile friendly.
Describe all imagesAll images must have an HTML <ALT> tag, describing the image with relevant and informative text that ideally is related to a keyword, and not "Click Here".
If an <ALT> tag exists on it's own in any graphic the text is displayed when the user "hovers" their mouse over the graphic. The purpose of the <ALT> tag is to display alternative text if the user had the "Do not Display Images" option checked in their web browser preferences.
If an <ALT> tag is used with a graphic, add a <TITLE> tag to the image. This title text will be displayed if the user "hovers" their mouse over the image. This gives another opportunity to add more relevant keyword rich text to the web page.
If the theme of the web page is connected to Jaguar Cars, it would be advantageous to call the image "Jaguar Cars -XJ220.jpg" rather than the non-descriptive name "image1.jpg".
Finally, prior to any attempt to optimise any web page it is vital to be aware of common pitfalls when creating a web site. It is necessary to be constantly reminded of what not to do to achieve a high ranking site. Software tools such as Macromedia Flash can produce sites that look very attractive to human viewers, but any attempt to parse them can lead to a very low ranking with most search engines due to the difficulty in indexing the site correctly.