Wisdom from the centuries. When it comes to decluttering, focus on one category at a time, e.g., clothing (all the places you've got it), books, toys, papers, hobby equipment, furniture.
If you've got a lot of something, make it its own category. Collect all of that category together, which is the only way you realize how much you've got and it makes you able to see what you're really using and loving and what you're not.
Some things never change and there are ways to make things work if we want to. Thank you, Mozart.