For me, the cabinets under the sink in our bathroom were more like caves where everything got lost than useful space. I recently decided to tackle one of them and I was able to find good solutions for organizing it.
I used a small set of plastic drawers to organize all of the hair accessories we have. I have a drawer for rubber bands, one for headbands, and one for barrettes and clips.
I used a basket for all of the hair products. There is a basket for lotions and other skin care products, as well as one for nail polish and related items. Now I can bring the whole basket up to the counter and use everything. Then easily put it all away.
This page contains the following solutions.
I have a ton of room in my bathroom for medicine and such. Hiding it all behind mirrored doors that often didn't close properly was a pain.
In my bathroom cabinet, I keep a see-thru plastic jar with a screw on lid. When out shopping and I find cough drops on sale, I stock up.
I bought some shelving to maximize space in my bathroom vanity, but still was not satisfied with the bottom. I had to take things out of the cabinet one by one to reach things in the back.