Vertical storage is better than any other because it helps you to save the space, which makes it perfect for tiny rooms. Even if you have a large space, you can still add vertical storage to display some stuff. Here are some ideas to incorporate vertical storage into a bathroom, take a look at them and you’ll understand that you need them, too.
Built-Ins
If you have some space, do a built-in. A built-in niche behind the shower space can be done with shelves to store some towels and not only, and this is the sleekest and most elegant idea that always works. Still, you have to plan it beforehand because adding built-ins to a ready space might be hard.

This super bright tiered shelving unit in red will not only bring storage space but also will add color.
Vertical Shelving Units
A vertical tiered shelf is a perfect solution for lots of modern bathrooms as it really works. Such a shelf takes very little floor space but gives you a lot of storage. Most of such shelves are of wood but there are also some of metal, which is more durable. You can put one into any corner and voila, a storage space is ready.

A classic stained shelving unit is done with a fabric organizer and some boxes to declutter the space.

The black and white Scandinavian bathroom is perfectly fitted with stained shelving units.
Sleek Cabinets
A sleek vertical cabinet is another cool solution for a bathroom, and it especially works between vanities and toilets or showers and sinks as you can divide the zones with it. It won’t give you much space but it doesn’t take much either and is perfect to declutter the room.

This tall and skinny storage unit is a cool way to store and divide, it's a very practical solution.

This tall shelf is squeezed between the wall and vanity and it takes advantage of this awkward nook. (via hgtv).

A simple ladder for towels and a skinny shelving unit are a nice combo to get storage space without wasting floor space.
Shelves And Ledges
Various multi-tiered wall-mounted shelves, usual open shelves and ledges are the easiest way to add vertical storage to the space. There are many metal hanging shelves available in stores, and you can just attach some of them anywhere you want, and voila!

These clear acrylic ledges will give you enough storage space and everything will be aesthetically displayed.

This super elegant brass shelf allow to store and decorate and adding hooks will help hanging towels.

This tiered brass shelving unit is a cool idea that will match most bathrooms and will give enough storage space.

Place a tall stained shelf over the toilet, so you'll be able to use this often neglected space in the best way possible.

Shelves over the toilet will help you use this dead space to advantage.

This chic metal suspended shelf is a fantastic solution to store all the necessary things and hang a towel.
Ladders
I love ladders! A ladder is a gorgeous towel storage unit, and more than that, you can hang some plastic boxes or wire baskets to the ladder to make the storage more comfortable. A ladder is very sleek and almost doesn’t take floor space, while you can put on it a lot.

Wooden ledges are great for bathrooms with a farmhouse or cottage feel. (via savillefurniture).

A light-stained ladder with plastic boxes is a lovely idea for a modern bathroom, this is a casual vertical shelf.

A ladder is always a good idea for a bathroom: you can hang towels or shelves. (via placeideal).

A ladder can be used not only for towels but also for storing things. (via boldlyrise).

Hang wire baskets on the ladder and you will get a small vertical shelving unit. (via cleanandscentsible).
Carts
A tiered cart like IKEA Raskog can be another cool solution for vertical storage. It gives a lot of storage space and it can be moved anywhere, besides, it’s easy to clean.
On-Door Organizers
Use your door to advantage hanging some organizers, usually they are made of fabric but you can also find stained wood. Get inspired!

Add an organizer to the door to give a little extra storage space to the bathroom.