A useful feature in Civil 3D 2017 is the ability to create folders under most major categories or objects from the Prospector tab in the TOOLSPACE.
Object Folders serve as an excellent tool to separate design alternatives, element types, phases, and more. Setting up Object Folders is a relatively simple process, just create a folder, name it, then drag and drop objects.
For example, organizing Surfaces:
Another useful application is the sorting of Alignments: