I need some ideas to increase/organize a bathroom linen closet

So no shelves whatsoever?

At the back of the shelves, you store things like extra toilet paper, paper towels, body wash, shampoo, etc. Also at the back you can put things like the towels and sheet sets you use when you have company and don't use them a lot. You can use the back of the shelves to store things that aren't used often, even small kitchen appliances can be stored on shelves that big on the upper levels. Use the upper level to store things like blankets, flannel sheets, etc that are seasonal. The bags that you vacuum down work really well with linens, even pillows, they come out when needed and are clean and ready to be used. If you have the room on high shelves, you could even use the vacuum bags for some seasonal clothes storage. In the front of the shelves, put the items that are used the most at the quick see and grab level. and go from there. I store sheet sets all together in one of the pillow cases so that each piece doesn't have to be searched for when you need them. Go up and down the shelves according to what is used the most so that it is assessable. On my bottom shelf I keep things like rags, old washcloths, the dreaded white towels, pet supplies like brushes, shampoo, nail clippers, clothes brushes, shoe insets and assorted other notions. I hope this helps!

great answers above! try using the wire racking systems at the hardware stores. great to work with and you can get different sizes for your needs.

Wire for drawers or baskets so you can utilize the largest area of the closet would be best. If you stack things in the back and put things in front, it is a pain to get to the items in the back because you have to move everything from the front. I would put shelves back into the closet - probably more than were there originally. Wire shelves take up less space than wood ones, but things can tip over (bottles/cans) more easily also. Make sure your shelves are spaced so you don't waste vertical space but you can easily fit in the items you usually store there.

Sliding wire shelves: https://www.amazon.com/wire-cabinet-drawers/s?page=1&rh=i%3Aaps%2Ck%3Awire%20cabinet%20drawers

Wire baskets: https://www.target.com/s/pantry+storage+wire+baskets

Or: - love drawers for any storage because I can always get to things in the back!