If you live in, say, a studio apartment or in a school dormitory, storage space for the items you think you need is at a premium. You do not want to clutter the room, yet you cannot live without those articles and conveniences of everyday living. The headache is worse when the wall storage units and the built in cabinet are already full and you still need more storage space. But some ingenuity on your part can free up space or utilize unlikely places for storage.
Under the bed: Usually this space is used to place the shoes and other loose small items for easy retrieval on demand, but if you consider it much space is wasted here. Above the shoes and immediately under the bed is much unutilized space. By making a chest of drawers that fits under the bed, you can use this precious space optimally. In fact, it will help you more if you make a bigger chest, even if you have to raise the bed a few inches to a foot just to accommodate the larger box. In it you can store your extra bed linen as well as your shoes, shoeshine items, slippers and socks.
Above the bed: You only actually need room enough for you to sit on the bed when getting up, so above that line space is mostly unused if it is not a two-tier bunk bed. Therefore if a similar box of drawers supported by legs can be fitted there, you gain much additional space. Naturally it may make you feel a little cramped, but you get used to it after a while.
Inside cabinets: You would think that cabinet interiors are fully used, but actually, much space always exists between the shelves and the top of the stored items. By fitting in small carton, plastic or wood boxes, you can use those spaces to keep your small items -phone chargers, pocketbooks, cuff links, ribbons, spare buttons, sewing kits and myriad other things. You can pull out the boxes to add more items instead of allowing them to clutter the room. The idea is to use that mostly wasted space inside the cabinets.
Room corners: Buy or build racks designed for room wall corners and you will be glad to see just how many items you can put there to reduce room clutter without constricting human traffic passages.
Over the tank: Many are using this space above the water tank for racks and shelves to store bath items. The racks are usually wire coated with plastic to reduce corrosion in the always-humid environment, or there are all-plastic ones you can buy. Secure the racks via suction cups to the tiles if you do not wish to damage the tiles.
A caveat: However, overdoing the storage idea may make your room look like a warehouse, so be selective and prudent. If you can, study the ancient Japanese ways of making their small rooms admirably uncluttered and simple by storing articles in discreet cabinets and decorative boxes. It will help you greatly.