For best possible search engine optimization (SEO), keywords and keyphrases must be used appropriately within the text of pages.  This includes page titles, sub titles, headers, bullet lists, photo captions and regular page text.

Make text readable by search engines
Most of your page text needs to be typed as standard HTML which can be “read” by the search engine bots that regularly visit your site. The font must be available on nearly all computers. If a particular font is not available on someone’s computer, they will see it in a more common form (such as arial, Tahoma, Times New Roman).

Flash movies and images can’t be “read”, so any text contained in them does not count. This means that a completely Flash site might have horrible rank, making it less likely to draw visitors from organic search results. A site using images to display fancy text would face the same dismal results.  If vast majority of visitors don’t come from search engines, this is not as important.  Examples would be membership sites where only members are invited.

Searchable text must include targeted keywords, with an optimal “density” of 3-4% for each particular word or phrase. This means that if there are 200 words on a page that you want optimized for the phrase “black shoes”, you should try to incorporate that phrase 6-8 times. Any more than that and you may actually be penalized for “keyword spamming” by a search engine – lowering your rank rather than increasing it! 

Create distinct pages for each search term so that any single page might rank highly enough to appear within the first 3 pages of directory or S.E. results, even if it is not the actual home page. If you have several products or services, give each it’s own page where you can highlight the distinct terminology and characteristics. When the differences are slight, consider writing a page or article on one of them where you merely replace one possible keyword for another. For example, you may use the word “car” on one page and “auto” on another page.  Even then, you should edit the text to avoid a possible “duplicate content” penalty.

Utilize heading tags appropriately
HTML heading tags (h1, h2, etc.) carry more weight than standard text since their purpose is to show a hierarchy of importance. Try to work keywords into the highest level tag possible. Having headings and sub-headings also makes pages easier to browse by humans! Sample:
<h1>Main Heading</h1>
<p>Paragraph of text describing heading</p>
<h2>Sub Heading (work in some additional or secondary keywords)</h2>
<p>More text…</p>

This is a case where having a human web designer or at least good software is always preferable than most word processing web page generators. That’s because the word processor uses it’s own code instead of the standard heading tags favored by search engines.

Multiple subheadings, short paragraphs
Keep pages “skimmable” with the generous use of subheadings and white space. Make it easy to pick out important terms when visitors are quickly glancing at a page to see if it contains worthwhile material. They can then concentrate on sections of text that give the information they need. More meat and less filler! You can always link from there to ‘more details.’