I have been on both ends of the spectrum, from fairly tidy to well, the opposite, yet my closets have always been messy.
We are selling our house, and our realtor paid a stager to come in and place our furniture and give recommendations of what to do to make the house look better. Anyway, it was great, but the best thing for me was the closet tip she gave. She told us to go the the office store and get those inexpensive file boxes. Then we put all the stuff on the closet shelves that looks orderless into the boxes and LABEL them. She also said don't go through stuff endlessly, this is not a time to pour over old photos or report cards. I think we all know that part, but it bears repeating. Put the boxes back on the shelves with labels facing outward. Then when you are really ready to organize your photos you can just get that box down and go to town, without getting sidetracked on other stuff.
All of our closets look fantastic, and it didn't take long at all!