My big thing was saving clothes. Way too many with 4 kids. So I simplified. I started saving only favorite items I KNOW I will use in the future, like the boys' special dressy outfits. I got rid of almost all my baby stuff. I have saved only a few favorite or barely worn items from DS1 down to DS2. Sometimes seasons are wrong and things don't fit, yk? I buy and save black snowpants because they work. I have saved a lot of shoes and boots, I might pare it down some too but like this winter it actually saved me having to buy boots for the younger 2. DS1 got a pair from a friend, DD I still need to get
The other big thing with kids is organizing TOYS and not having so many. I gave each child an under-bed tote, I allow one other box in their room for bigger stuff, like DS2's trucks. Then I have games and puzzles put up so they have to ask, and they must pick up the first before getting another. I also way downsized our books. And what *should* probably be a linen closet outside our bathroom is 2 shelves are an arts-and-crafts area for them. Paper organized, colors and such in a 3 drawer plastic thing, playdough box. At their level.
I got one of those shoe things that go over the door for inside the coat closet for all the mittens, hats, scarves, all that winter stuff. This summer it held flip flops and stuff like that.
The other thing is I have magazine holder things--and ones I made with duct tape reinforced cereal boxes! to hold school papers on top of the fridge.
Oh and my bedroom closet shelf is mostly a bookshelf, with boxes of 'stuff' as bookends and I can close the closet and not look at it.