You can use LongListSelector as a glorified ListBox, but that cripples its true purpose. The real power of LongListSelector is to display long categorized lists, enable a "People Hub" style "jump list" to navigate between groups in the list and to allow performant scrolling.
Grouping
The trick to get LongListSelector working is to properly group the data assigned to the LongListSelector ItemsSource. You can start with a simple flat list of objects, where each object has a property suitable for grouping. In the snippet below, "MyObject" has a "Category" property that the list will be grouped on....