The hardest parts of a website re-design or improvement are the aspects of the site that are not immediately visible. We can all form a quick opinion on the look and feel of a site, but critical aspects, like usability, navigation and user experience, are harder to assess. The way a visitor can and does move through a site shapes their experience on that site in a significant way. It is not enough to make a site clean, informative and aesthetically pleasing, the controls and navigation must be intuitive and clear as well. Page organization under category topics must be logical and functional. Once the user has found the desired information, they must be able to easily navigate back to the start, or onto related pages.
It is often difficult for designers and developers to assess the usability of a site, as they tend to be over-familiar with the design and the back-end, and have never been a true user of the site. When implementing a re-design or new navigation, have colleagues and associates test the site for these navigational and usability issues, and take their feedback seriously. Watch how they navigate through the menu, and how they use features of the site to find desired information. Then, if you must, give up some design high ground, and modify your structure to give your visitors the smoothest possible experience!