I have folders for years, and in those, I have a folder for each shoot.
I used to have subfolders for months, but there wasn't much point, not enough shoots per month to warrant yet another level of subfolders
I just have something like
2005\
2005\0829 TPF Test shots from Sigma 70-300
2005\0829 TPF Test shots from Sigma 70-300\IMG_1102.CR2
2005\0829 TPF Test shots from Sigma 70-300\Converted\
2005\0829 TPF Test shots from Sigma 70-300\Converted\IMG_1102.tif
2005\0829 TPF Test shots from Sigma 70-300\Converted\IMG_1102.psd
If that makes sense. I then, too, fit as many as I can onto DVD, and mark it as such, put it away, then have some rewritables with the same on (thus having two copies of the most recent discs in my posession).