The single most important aspect of any given Web site is its navigation scheme. Bad schemes leave visitors confused, stranded, and frustrated, which translates to less repeat traffic. Upon setting out to design your site’s navigational scheme, first decide if you want a left-hand column or a header navigation scheme. You may even opt for both, in which case it’s a good idea to place those topics that will persist from page to page horizontally across the top of the page and subnavigation topics in the left-hand column. Drop-down menus can reduce navigation-bar clutter and provide more options but should never go deeper than three levels.
Additional rules for creating a usable navigation scheme include making it follow the logical order of your site’s content, including some redundancy to make sure visitors find what they need, and making sure you never strand your user. This means ensuring that wherever a visitor is on your site, he or she can always back up to the previous page, the parent topic of the current page, all major sections, and, most important, the home page.
For more on Web development, be sure to read New Web Development Technologies: Beyond HTML.