Top Ten Mistakes in Web Design       

1. Using Frames

Splitting a page into frames can be very confusing for users. When a user tries to bookmark a page from a framed site, they are usually returned to the main page that generated the frame, rather than to the page itself. 

2. Gratuitous Use of cutting-Edge Technology

Do not try to attract users to your site by including the very latest web technology. Most potential customers care more about the services you can provide than about how innovative your site is. It is better to wait until some experience has been gained with new technologies before you use them. Let somebody else's site crash when people try to use it.

3. Scrolling Text, Marquees, and Constantly Running Animations

Never include page elements that move incessantly. Moving images have an overpowering effect on the human peripheral  vision and get in the way of the real content.

4. Complex URLs

Although most users will access the individual pages of your web site via a menu system, some users will want to enter the URL of the page directly. If the page references are formed using a seemingly meaningless combination of text and numbers, it may lead to typing errors.

Use short names for web pages e.g. 'main.htm' or 'index.htm'. Do not use names like 'Welcome to my site' or 'pageD354'.

Do not use special characters such as   -   _ ~   as they are often confused.

5. Orphaned Pages

Make sure that all your pages include a clear indication of which web site they belong to, since users may access pages directly from other sites. For the same reason, every page in your site should have a link to your home page.

6. Long Scrolling Pages

Some users will not scroll beyond the information that is visible on the screen when a page comes up. Consequently, all critical content and navigation options should be on the top part of the page.

7. Lack of Navigation Support

Do not assume that users know as much about your site as you do. They always have difficulty finding information, so they need support in the form of a strong sense of structure and place. Start your design with a good understanding of the structure of the information space and communicate this structure explicitly to the user. Provide a site map and let users know where they are and where they can go. Also, for larger sites, it is a good idea to make a search feature available. 

8. Non-Standard Link Colors

Links to pages that have not been seen by the user are blue. Links to previously seen pages are purple or red. Do not mess with these colors since the ability to understand which links have been followed is a navigational aid that is standard in most web browsers.

9. Outdated Information

If your site contains outdated information, customers that base their decisions on that information may complain.  If you have a reasonably large company, it may be worth employing a single person full time just to update your site. Maintenance is a simple way of enhancing the content on your website.

10. Overly Long Download Times

Many users will not wait more than ten or fifteen seconds for a web page to load. There is no point in having high quality multimedia content if users will click elsewhere before it has downloaded. If you want to include high quality multimedia content (such as Flash movies), try to have something happening on the screen while the rest is loading. This might be a progress bar or a short piece of  text that seems to type itself onto the screen.