Back in the 90's when I was completing my Secretarial course one of my work experiences was in an Accountants. I would spend one day a week for a term there and on about the third week I was shown the Filing Room. Wall to wall filing cabinets with lower ones in the middle also serving as a giant table. I was granted the privilege of shredding - literally big black bin bags of paper. I think that might be why I like the modern day filing methods more. So here's a couple of suggestions:
If at all possible then go paperless. I realise that won't work for everything but in most cases it will. By getting out of the habit of printing everything the business will benefit in multiple ways - space won't be taken up with filing cabinets, costs of paper or ink are reduced / eliminated, better for the environment.
The Cloud Is Your Friend
Over the years at home we've gone through a few PCs and had grown to form the habit of backing up everything onto portable hard-drives. Which is great until one falls on the path!!! Then a couple of years ago I was using my portable hard-drive to store files while transferring from PC to laptop and it stopped working. I lost 4 years of baby photos among many other files. Ever since that I save everything on OneDrive. I know some people think it can't be very secure but to me it's even better than on the local PC or paper copy. Files and folders can be password protected too for added security.
Whether you're going paperless or on the Cloud labelling correctly is vital. There's nothing worse than looking for a file thinking it's labelled something quite obvious like 'Light & Heat' and someone abbreviates it to 'L&H'. Best labelling is done with full words rather than abbreviations.
It's just as important to file emails correctly as it is paperwork. If you get a lot of attachments it might be a good habit to form of saving them on the Cloud too. Keeping your emails filed means you aren't looking at thousands in your Inbox everytime you log in. It also gives you the opportunity to delete what's rubbish.
Do you have any more suggestions?