Use baskets for organizing liquids (vinegar DIY products, etc) -- this was a great organizational idea. My sprays and bottles are now lined up in two rows. They look neater and it makes a little extra space down there.
Clever Slivers...Bathrooms often have small footprints but plenty of unused vertical space. A tall but narrow cabinet can be used to store toilet paper, towels, and toothbrushes. Look for a model that has both closed storage (such as cabinets and drawers) and open shelves to both conceal items and provide easy access to everyday items.