Design for Optimal Navigation

Navigation bar	A graphical element with hyperlinks to all the major parts of a website
Site map	Shows users how the content is structured and gives them a quick way to move around the site
Pull-down menu	Instead of typing in keywords, users choose from a list
Main menu	Lists the site content, usually on the home page
"Breadcrumbs"	Hypertext links at the top of a page show users where they are and the path by which they got there
Index	A list of site content usually placed in a frame that appears on every page

Improve Website Navigation

Just about every website has some form of navigation. Unfortunately, not every website navigation is good. Most of the time, the navigation of a website is put together by people who know how to design websites but do not know how to create a good user experience.
The designer knows very little about marketing a website or creating a website built for the customer. Just because your navigation is built into the site does not mean it is doing the best job of giving your visitors what they want. Navigation can make or break your website's overall performance when it comes to retaining visitors, keeping them engaged and driving them through the conversion funnel.
Strong site navigation makes it easy for visitors to quickly find the information that interests them, sans a potentially frustrating hunt. It also helps search engines index your important information efficiently and effectively. Conversely, poor navigation does more harm than good since it confuses visitors and causes them to abandon the website. When they cannot find what they are looking for, you do not get the conversion you anticipated.