I used to have my embroidery files in categories but would rename the files to a name that would describe the file. But that got time consuming and tedious. Then I ran across a free program called Embrilliance that let you view the thumbnail of the design in Windows explorer. So now I simply create folders in categories and copy the files into the appropriate folder. I also have subfolders such as "birds" which is a subfolder of "animals". I sometimes will file a design under more than one folder. For instance if I have a design that has both flowers and birds I'll copy it in both a bird's category and a flowers category. I also file my designs in source of purchase categories, whether they were downloaded from cd's or from embroidery design websites.