Shower caddies usually hang from your shower head to add useful bathroom storage, but you can also use them out of the shower too. Just add a few Command adhesive hooks to your wall and hang a caddy anywhere you need extra space. Image from The Crazy Craft Lady.
Aimee at The Crazy Craft Lady tried this out, and found that 3M Command hooks (like these from Bunnings) stuck well and supported the caddy's weight. Find the best spot for the hooks by holding your empty shower caddy against the wall at a height that you can reach comfortably and mark it with a pencil dot. If a few people are using the shower, each one can have their own caddy at the height that works best for them. That way everyone will have enough room to keep all their bathroom products handy, and you won't have to move a bunch of bottles every time you clean the tub.
Dollar Store Bathroom Organising [The Crazy Craft Lady]