This summer I organized my fathers files. He had a large drawer full of papers, sorted into just 4 giant folders. I found a great organizational tutorial on pinterest, and hopped over the website to get the details. Aside from the colored folders (I used colored labels instead) I made almost no changes to the method.
Now for my files, it was all digital. I have sorted my files into similar folders and sub-folders as my dad's files. And then each file is actually named with a last name, first name, birth year, and description.
It really makes it easy to find things when they are well organized.