here is how I manage mine:
1. I only keep things I will actually wear. Many things I get from hunts are fine but not my style or color...so even if it is nice I delete anything that I don't love. I also delete all calling cards...never have been sure of their purpose. I hate gestures...I deleted all of those too. Scripts and textures, I only keep the few I will use. Notecards can quickly get out of control make sure your delete any unneeded ones daily. Getting rid of any items you really wont wear, need or use is HUGE. If it is bad, ugly, doesn't fit right, old,or just not for you trash it!
2. Transferable items...if I have anything that is transferable, older, and it is not a favorite item I give out to nooblets or to a friend who resales. I have too many newer things I love why hold onto the old I only have so many hours to wear the good stuff.
3. I box up holiday items like Christmas/Easter outfits/decorations anything that will only be worn/used for a specific time period. I box up any furniture and landscaping items I do not need for my current home
4. With the new "Add" feature I have deleted all items for multiple attachments...like the belt you have that can attach to spine then another of the same that will attach to stomach, pelvis etc. I now just keep one. Also make sure you don't have duplicate items in outfit folders...use the new links instead to organize looks
5. If a dress or other item came in 4 colors I just keep my favorite...why would I want to wear same dress over and over just in different color...I have too many other choices!
6. I organize categories with sub folders: Clothes= Dresses, Lingerie, Outerwear-like Jackets, Pants,Skirts, Shoes: Then within those have sub folders like Dresses = Mini, Maxie, Evening, Summer Only, Winter Only, for shoes I have Heels, Flats, Boots, Short Boots. I do same for any large category like Hair= updo, tails, long etc
7. Landmarks I put on notecards: Hair Lms, Jewelry, Shoes etc They are easy to keep updated
8. Have a inventory cleaning day or days with a friend. It is boring to do a major clean up so get a friend who needs to do the same come and chat with you while you both work
Hope that some of this might work for you --- happy inventory cleaning!