Out of the box means that you are able to think of ideas that may be different from what you are used to. There are certain situations that will let you know immediately what your possible options are. Thinking out of the box means that you will look beyond those options and think about what others things you can do instead in order to improve your current situation.
There are times when you can think of things that are never done before. You will be surprised with the positive outcome that you will get in the process. Just remember that you may need to become creative in order to think out of the box.