Depends on the type of item.
TonyDedo asked about magazines/holsters/mag carriers etc for different guns.
I use the snap lid, plastic food storage boxes. Buy the cheap ones at the Dollar store. They stack nicely on shelves, and can be labelled with either computer printed stick on labels, a label maker or just a marking pen. They're in a converted closet off my 'office'. (There's more in there.)
Reloading components go on Rigid Rack or Gorilla Rack shelving. Bullets on one, brass on another (two, actually, rifle and pistol calibers), and powder and primers on different levels on a separate unit. This unit is cased in one inch plywood to satisfy 'universal fire code' specs.
The bullets are in original boxes, usually, but some (the .32 auto stuff) is all in one ammo can, but still in original boxes. In the reloading room in basement.
Brass is stuffed into ammo cans with hang tags from the stationary store on the exposed end showing contents. I tried stick on labels, but the labels I bought didn't stick to the can very well. I'll have to try again. In the reloading room in basement.
Primers and powder in original packing and spaced out a bit. Shelf in a private area away from reloading room in basement.
Loaded ammo in plastic ammo boxes on a different shelf in the powder room in basement.
Reloading dies and tool heads (Dillon XL650) are right now just on the end of the bench. I'm working on a wall mounted cabinet that will hold them in a rack and not rest on the decapping pins. All the 'switch parts' for caliber changes are in a 'parts organizer'. In the reloading room in basement.
Range equipment - chronograph, range box with tools, earmuffs, rifle rest, spotting scope and such are in a converted closet off my 'office'. Shelving holds variations on tool boxes holding all the stuff.
Gun belts are on clothes hooks in the same closet.
Targets are a mess. I'm putting together another shelf unit with fairly wide shelves to store targets flat. That will also be in the basement.
Yes, I'm single and own my own home. Don't hate me for this; three women already do.