If you have to use a garbage can lid as a sled or a set of drapes as a ball gown, then you know what it means to put together a makeshift creation. Something makeshift has been improvised, thrown together with whatever is around.
What's interesting about makeshift is the way it can vary in meaning from approval to criticism. Those people trapped in the island in Lost? They came up with some pretty cool makeshift tents and survival ideas. But a government described as makeshift, for example, probably has little going for it.