(1) Common actions should require as little effort as possible and should be obvious; on the other hand, actions that are rarely needed can be require a lot of steps and can be hidden behind menus and dialogs. To be able to do so, you should always describe what the user will want to do with the application by listing use cases.
(2) A UI should be selfdocumenting. The manual should be integrated in the application's dialogs and menu's, as users don't read separate manuals. For example, the keyboard shortcut should be shown in the menu item representing the action it is associated with.
