I sort my characters into what they are / what they mean to me. I then also have a folder for projects that are my wip characters that I haven't really designated any spot too.
by how much you like it? by theme? by story? tell me :)
I make a plan to organize my toyhouse and then never actually do it...right now the best I have is a vague sort of organization by main ocs, mmo characters and then cs -- but a lot of my mains are also hidden and my secondary/tertiary are no longer retentive since a lot swapped places and I'm too lazy to fix it. I have what I need to do on paper -- by universe, basically -- but that means fixing a good chunk of ocs which aren't visible to public and uploading a lot that aren't even on site so it's not just one/two per category for some things. And damn that's some effort.
This is the reason my th is always a mess and will probably remain a mess.
Right now I organize them by the one folder of never trading and the rest as character types; Humans, Animals, ARPG, etc.
I just threw all of my ocs into a few folders; the main one is All Characters. There are three tiers, depending on how much development and attachment I have to an oc, a Needs Personalities section for characters that are only just designs right now and a Needs Art folder. Oh, and I got a Game-Created folder so I can throw characters and such I met in video games like MC and other games so I can develop them later on and so I'll never forget them. Everything is sorted Alphabetically because I don't want to sort and resort things all the time.