Wire fruit baskets: cool for holding apples and oranges; amazing for holding bath products. Hang one from a shower rod or in the corner of your bathroom. Double the amount of storage space by hanging two together.
Lip balms, hair ties, bobby pins, bath salts -- all the annoyingly small goodies littering your bathroom drawers can be corralled in this wall-mounted spice rack. This homemade version and many others like it are available on (surprise!) Etsy.
Nail a couple hooks to your wall -- or, easier yet, buy a set of over-the-door towel hooks -- and hang a pretty basket on them. You get as much horizontal space as you would with a small shelf, and you don't even have to waste a half hour looking for your level and measuring tape.
A simple wood ladder or stepladder = InstaShelves! Take 20 minutes to pretty it up with a couple coats of spray paint or leave it bare and watch "New Girl" instead. (No judgment.)
Not all manufactured storage products resemble Tupperware containers for giants. See: this sleek, practical option from Duravit.