Items Have No Home
Simply put, you can't put things away if there's no place to put them. If items are piles all over the place, it is likely that you never designated a particular spot for them. In other words, the item has no "home."
Solution: Take the time to assign each item a single, consistent home, e.g. hats always go in this basket; scissors always go in this drawer. Label everything so you'll always remember where it belongs and easily find it when you need it.