From http://www.w3schools.com (Copyright Refsnes Data)
Designing Web sites needs careful thinking and a lot of planning.
The most important thing is to KNOW YOUR AUDIENCE.
If you think a typical user will read the entire content of your Web pages, you are wrong.
No matter how much useful information you put into a Web page, a visitor will only spend a few seconds scanning it before they decide whether to leave it or to stay.
If you want a visitor to read your text, be sure to make your point in the very first sentence of the page. After that you should try to keep them occupied with short paragraphs and interesting new headers all the way down the page.
Try to keep all sentences as short as possible. Try to keep your paragraphs as short as possible. Try to keep your chapters as short as possible. Try to keep your pages as short as possible.
Use a lot of space between your paragraphs and chapters. Pages overloaded with text will kill your audience.
Don't place too much content on a single page. If you have a lot to say, try to break your information into smaller chunks and place it on different pages. Don't expect any visitor to scroll all the way down to the bottom of a page with thousands of words.
Try to create a navigation structure that is common for all the pages in your Web.
Keep the use of hyperlinks inside your text paragraphs to a minimum. Don't use hyperlinks inside text paragraphs to send your visitors to every random page of your Web. That will destroy the feeling of a consistent navigation structure.
If you must use hyperlinks, add them to the bottom of a paragraph or to the navigation menus of your site.
A common mistake made by many web designers is to develop a site on a local machine with direct access to the data, or to develop the site over a high-speed Internet connection. Sometimes developers are not aware of the fact that some of their pages take a long time to download.
Internet usability studies tell us that most visitors will leave a Web page that takes more than 7 seconds to download.
Before you publish any content heavy pages, make sure they are tested over a low-speed modem connection. If your pages take a long time to download, you might consider removing some of your graphic or multimedia content.
Feedback from your users is a very good thing. Your visitors are your "customers". Very often they will give you some valuable wisdom, or advise you, completely free of charge, about what you could have done better.
If you provide a simple way to reach you, you will get a lot of positive input from a lot of people with different skills and knowledge.
From http://www.w3schools.com (Copyright Refsnes Data)