For best visitor retention and sale conversion rates, use conversational tone and provide plenty of text to generate interest. Use the terms that people are searching for.

Speak in simple language
Explain in terms that the average visitor would understand. Avoid using industry jargon when your target audience is the general population. It’s easier to trust you if they understand what you’re saying.

Keep text easy to read
Use short sentences. Longer sentences are often more difficult to follow. In most cases, a conversational tone will be more interesting and readable than a scholarly explanation. Don’t put too much information on a page. Instead, “continue” on to additional pages.

More text = more content
Don’t skimp on the total amount of overall text. Think of a search engine as a hungry tiger and your text as meat. Feed the tiger! Give it lots of juicy text to chew on. As long as page length isn’t excessive, more applicable words on a page means better results. You can work in many more keywords and keyword phrases in 300 words than you can in 100 words. As long as you break up the text with subheadings, bullet points, and graphics, human visitors will devour it as well.

Repeat yourself (again and again?)
Drive home important points by explaining yourself in a number of ways or by providing examples to illustrate details.

Put critical information near top of page
Important points and ideas should be visible “above the fold” to human visitors. Help them easily find key content without becoming impatient and having to scroll for it.  Long pages could include some links to “jump” to lower sections of that page.

Place targeted keywords prominently on page
Keywords that are introduced towards the top of the page actually count more towards that page’s search engine ranking as well. This is logical in that the main theme of any page is expected to be discussed at the very beginning. Think of each page as having its own headline, lead paragraph main discussion points, supplementary or supporting information, and finally a summary (including a call to action like “Sign up now!”). Thus, the first and last paragraphs on any page should emphasize the targeted keywords.

Use bold text for keywords
Where your targeted keywords or keyphrases appear on pages, make them appear in bold text at least once or twice to catch the attention of visitors and tigers! Using HTML, these tags are placed around the words: <b>word word</b> 
Yes, search engines give these highlighted words additional increments of credit towards pagerank!!!

Use the word “Free”
Find a way to work ‘free’ – in bold letters – into your site, especially the home page. You probably have something that you can give away, even if it is a PDF full of good advice. The internet was built on the premise of ‘free’. In fact, your customers may have typed in ‘free widget’ as a search term!

Use the words “Today” and “Buy now”
Why wait until tomorrow? Order now! Don’t delay! Take advantage now! Enjoy our product today! Be the first on your block! Foster a sense of urgency. Your visitors are looking for reasons to take action. Facilitate the process.