Over a decade of business let me with several file cabinets filled with hanging files relating to client projects, business records, design ideas, maintenance and operating manuals, publications, inventory files, etc. I felt they were reasonably well organized by general category but when a critical volume was reached I had a hard time finding an individual folder or when a file was removed for use I lost track of where it was located.
This year I was able to devote time to organizing them. I settled on a numbering system, somewhat like the Dewey Decimal system, which allowed the files to be grouped in large general categories and subcategories and numbered so that I could search a computer database and find precisely where the file resided. This took quite a few tedious hours to set up and still requires some attention to maintain but it is already saving a lot of frustrating searching time.
Most of the files are up in the loft which is generally cleaner that the rest of the space. If, for instance, I am working on a door knocker for a client I go up and get the door knocker design file and bring it down to the file cabinet by my layout table. On the computer database it is given an additional number which shows it is now temporarily residing with the work-in-progress files. When the project is finished the files goes back upstairs. It is a bit awkward to explain the system fully and I suppose each individual has to find an organization plan which suits their needs. This works for me.