Here's my recent system to keep things tidy.
As most I have 3 hard drives in my DAW.
My 1 TB C drive is Partitioned into C= 178 GB and a G = 780
My working Sonar and Wave Lab files are all on G , audio storage only nothing else.
For Sonar projects there is a main folder for each "album"
Inside those albums are the individual folders for each song, therefore the CWP and Audio.
Then I have an F drive where copies of these same folders are stored.
I routinely back up the entire "Album" folders and date them. I keep at least 3 copies of each album until the smoke has cleared. I also routinely perform "save as"to these locations as I work.
Then there is a H drive where when a song is finished I will perform a "save as" so that copy will be clean and only have the exact data needed. These files are then archived to a external drive and my H drives are removed from time to time and put on a shelf.
I will also back up the album folders and date them to an external drive when I have time at least once a month.