I'm another who uses LR to organise my images. I would really recommend a system that uses database tools to organise images. I used to keep all my images in dated folders, but eventually you need something more. The hardest bit was going back and doing the keywording for all the old images. LR makes it really easy to apply keywords on import, so I add all of the simple stuff like event details in bulk while importing the images. For my aviation subjects for example I will then go through and add image specific keywords, such as aircraft type. Although this may take a bit of effort it is quite possible to do a full airshows worth of images in a hour or two, even when I may have in excess of 1500 images. Adding the keywords to multiple files is as easy as a single file, so you usually only have to do a dozen or so groups. In other situations, where that level of keywording is overly complex the images may not get additional keywords added. I also make use of IPTC subject codes, as LR can also make use of them.
Once I have tagged images LR offers many different ways of sorting images. You can make collections of images manually by simply draging and dropping, what is good, and beats just using the file structure, is that the same images can be in as many collections as you like. LR also feature virtual copies, so you can also have more than one version of the image, with only minimal extra data storage, you don't have to copy the original file. As well as manual collections LR has Smart Collections, which a made up of stored searches, which allows you to group the images by pretty much any detail stored in the images EXIF data. You can also have collections of collections. Of course you can also sort manually from anywhere within the Libary module to further refine your visible images.
I use LR so know its features well. There are other similar database systems avilable, if you do not want to use LR. I just cannot give you details.
Alan
