For clothes
Lay out all your clothes and make outfits or uniforms from what you have for five to seven days. Remember, you can wash your clothes, so you might not need a full seven days of outfits.
You can try to set up your wardrobe using the below example.
1) A couple of weekend casual outfits
1b) A couple of business-casual attire
2) Suit pants or skirt for business formal attire
3) 1 pair of dress heels, 1 pair of flats, or similar footwear, or men's dress shoes color depends on job environment.
3B) A pair of sneakers for casual outings
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For your room.
Try daily tracking of what you use vs. what you don't.
Keep any item that is essential to your daily life routine (hair, skin, dental care, etc.)
Also, any items that you do not use for a month or two, put them in a clear storage box. If by 90 days, the items you have put in the storage box have not been needed, then donate them to the charity shop.
Take your time, and do not rush to get rid of things.