When adsense denies your website based on navigation and usability, then you have to pay attention to theme.
Does your theme has menu at the top? Does your site has sitemap? If not, then you have to change the theme. You have to use the sitemap in the footer or the top menu. This way your site becomes easy to navigate. Also do pay attention to top menu. The reason being menu allows navigation easily. And not having such menu with all options, makes it harder for access.