My film gets put in print file sheets and labeled on the top as to subjects and date. All are put in a binder in approximate chronological order and are separated by film size and type - ie, I have binders for 35mm B&W, 35mm E6, 35mm C-41, 120 B&W.... I mix Hasselblad and P645N in the same binder (with Holga and folders that take 120). Each roll of film gets a number based on order and the contact sheet for that roll gets that number on the back. The contact sheets are usually way out of order and in various piles.
The system isn't great, but I can usually find a neg fairly quickly. There are also post-its sticking to some rolls with shots I know I like and want to print again.