I have found that the key to successfully organizing your images is to build a structure that starts with the largest logical categories and moves downward to progressively smaller sub-categories. Step One is therefore to decide what you want your largest categories to be. For example, if you're working with film negatives and transparencies, you might decide to first divide them into black & white and color. If they're all color, you might decide to divide them into color negative and color transparency. If you have different formats, you might decide to separate them into 35mm, medium format, and large format. If they're all digital, you might separate the original Raw files or JPEGs from files that have been Photoshopped, re-sized, backed-up, and so on.
There's no one right way, but you should have no more than 3 or 4 major categories, each of which can be sub-divided into smaller sub-categories. In my case, I separate my film archive into black & white, color transparency, and color negative. Each type of film stock is kept in separate binders with different colors. Digital files are stored on my hard drive in folders separated by year and shoot date (month and day of download). Depending on what kind of image I'm trying to retrieve, I can instantly narrow my search to one of three groups of binders or to a single folder on my hard drive.
The beauty of this system, especially for those of you who don't already have one, is that the fewer major categories you start out with, the quicker it is to do the initial sort and thus the more likely it is that you will do it. If you're shooting digital, the added benefit of having a logical file structure is that it's easier to back-up--and without back-ups my friend, you may one day discover you have no images at all.
My next post will explain Step Two: How to set up sub-categories. In the meantime, feel free to share any questions, comments or suggestions you may have.