Use Wall Space
By adding shelves, you can have towels at your finger tips ~ something that comes in handy if linen closets are scarce.
If you have items that aren't suitable for display, try attaching fabric to a cafe rod to hide those items or in this case, affix hemmed fabric with upholstery nails.
Apothecary jars are a great way to store small items such as q-tips, cotton balls, and bath salts.
Glass shelves have been added between wall studs. This is probably one of the best ways to add storage without taking up visual space. These shelves are painted to blend with the room, but a background of wall paper could be a fun pop of color.
Use the Door
This is a fun idea for a kids bathroom. Rods, normally used in a kitchen, are put to use in the bathroom holding holding towels and toiletries.
Another kitchen item being put to use in the shower when built in storage isn't available.
(All photos are from BHG)