One of the things most often overlooked is how to set up your WordPress website for content management. I've seen some "Frankensystems" where pages and posts are all mixed together. If you have hundreds or even thousands of pages it can be a nightmare to manage.
One of the easiest ways to set up the admin is to create custom post types. These are posts that don't fit into "posts" which are the blog and "pages" which comes with WordPress. By setting up custom post types you are creating what is called a taxonomy which is a complicated term for categories.