adjust disarranged files in the file server

Hi all

I am now supporting architecture office in Tripoli; recently I asked them to adjust their files structure in the file server. As I am system administration, their disarranged file makes many problems such as duplicate files, low hard drive capacity, difficulty to backup their data and to find the files.

Is there any recommendation from you as technical peoples, which help me to advice the office to structure their files and folders?

Thank you