I'm not a natural organizer, but I find much peace in being organized. So I organize. Some times my attempts work beautifully and other times they leave much to be desired.
Here are two that have worked so marvelously well over the years that I'm surprised they came from my personal brain.
1. We were constantly losing cards or game pieces and when it was time to play, we couldn't. In our play room I placed a small basket (plastic box, whatever) on top of the shorter bookcase. Whenever we're cleaning or digging things out from under the couch and we find a game piece or card or something we set it in the basket. If we want to play a game with a missing piece we check the basket first. About once a month I'll go through and put all the lost parts in their proper home.
2. We're a reading family. And we never had enough bookmarks so my kids would use dirty socks, toys, the dog leash, whatever they could find to mark their places and many books were damaged in the process. I put together a stack of bookmarks and put them in the corner of a shelf on one of the bookcases. They now know that whenever they need a bookmark, they can go there and find one. When they're done with one they return it to the same place.