Make cross-structure navigation easier

Make sure your visitors can easily jump from one category to another, without having to click the Back buttons multiple times. This is why it is important that you list all the top category links somewhere prominently on every page. In fact if you are planning to have a complex structure, then you should create a drop-down menu with as many sub-menus as needed so that with just a simple click or with very few clicks any page can be accessed.
Your website might be having great information, but if that information is not logically organised it will be very difficult for your visitors to access it. Make your information easy to access and your visitors will come to your website again and again.