One of the least glamorous but potentially most time and frustration saving habits you can acquire is to adopt a good file naming system and then use it consistently. A good file naming system can save you hours of time when you are trying to find an image. This is particularly true if you tend to save several versions of a file.
A complete graphic file name should include: item name, color mode, resolution, and file format. An example would be Trees_CMYK_200.psd. This type of attention to detail in file naming, while perhaps a bit cumbersome, will make your file management and location chores much easier. In addition, it will make it easier to identify your graphic images.