Avoid mixed case in URLs. All lower case is preferred for readability. URLs on certain UNIX servers are case sensitive and will not work unless the
Use relative URLs for portability. A properly configured suite of pages linked with relative URLs can be moved from one location to another with a minimum of reconfiguration.
Use HTML extensions sparingly. Certain elements such as the center tag are relatively silent when viewed with a non-compatible browser. Other elements such as tables will be unintelligible. If you want your pages to be available to the widest possible audience, stick with standard HTML.
Limit the size of graphic elements to less than 500 pixels wide. Many computer monitors have a resolution of 640x480. Eliminate the need to scroll your pages in two directions by limiting the width of your graphics.