...for myself:
I have a pics and a vids folder, each has subfolders (amateur women, amteur sex, blowjobs,...). Each subfolder contains a "shared" and an "on hold" folder so I can keep track of what I posted on here so far.
Usually when downloading pics from one site or another I usually name them right when I save them, unless it's just one single pic. Takes a lot of imagination to make up new names for new downloads after a while since the "standard" names are already all taken.
For searching duplicates I use DupeLocater, a small proggy some guy posted on another board quite a while ago. It runs pretty smoothly, but you have to be careful still, since at times pics do have identical sizes but are still different.
Dunno if this works, but I'll attach the proggy as a zip. Tested and found harmless on my side.
Hope this helps a bit getting your collection sorted and yourself ready to post.
Greets,
A Lurker