Content is King and providing content for your Website pages is the key to high Search Engine rankings. But spiderable content does not equal humanly readable text: graphical elements (*.gif, *.jpg, Flash or audio) contain information that's perfectly intelligible to human visitors but meaningless to robots. It's imperative to keep any content which you want spiders to read, well outside the graphical areas of the page. That includes links: the text anchor of a hyperlink is a strong element of content in many cases and by replacing the text anchor by a fancy looking button you will lose this advantage (adding an alt attribute to the img src tag will not let you regain that advantage). By separating all graphical elements from readable content you make the site readable both to bots and human visitors alike.
The title of the page is an important content element: include the main keyphrase in it and enclose it in the H1 (or H2) tag.
Write naturally sounding text about your subject, using the main keyphrase a few times, not too far from the top of the page. Include secondary keyphrases in the section headings and enclose them in the H2 (or H3) tags, where applicable.
Page length should be no less than about 250 words. Spiders rarely read much more than 300 to 400 words, so making your page length much longer than that will not influence the page's rankings much. But don't feel obligated to stop at any page length: say what you have to say without concern for length. Very long pages can benefit from being split into two or even three parts, to avoid that the end of the page never gets seen. Create a page break by inserting a "Read more" hyperlink, linking to the next page. At the top of the next page place a "Continued from..." hyperlink to the previous page. If the first page was called /page.htm then call the next one /page-2.htm.
The word count of this article is about 340.