Use a rolling pin holder as a curling iron holder. Just make sure its not tol wide for your irons -- I like this idea better than putting hooks on the inside of the cabinet and hanging them. This way there's no tension on the chord
Plant holders make great hair styling supply holders. Instead of hanging plants in them, you just mount them to the wall and put your blow dryer, curling iron and other hair supplies inside 30 Brilliant Bathroom Organization and Storage DIY Solutions
Find unexpected storage options in your small bathroom! Try using a wine rack for rolled towels, choose a mirror that has hidden storage, use adhesive hooks to hang flat irons or curling irons, and repurpose plant holders for easy wall storage.