Go Up, Not Out
Stand in your closet and look up. If you see empty space, you have an opportunity to take advantage of it with hanging racks, pegs or hooks. From pesky items, like scarves, to horizontally hung umbrellas, you can usually find a way to take advantage of closet space near the ceiling. If you're lucky, you may even be able to fit a couple of shallow wire shelves on the wall up there.