Hang a cloth shoe organizer on the back of your bathroom door. The pockets are the perfect size for bottles, not to mention hair tools.
Free up cabinet space for your multiple bottles of shampoo (admit it) by rolling up your towels and displaying them on a wine rack.
Step 1: Pick up wire paper trays from an office supply store; you can also find cheap vintage trays on eBay.
Step 2: Use them for storing bath and hand towels; stack 'em or hang multiples to maximize space.
Step 3: Let your friends think you bought them at Restoration Hardware.
Step 4: Put the aforementioned shampoo bottle collection in your towel closet. No one has to know.
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.