Let's say there are five issues that you are dealing with that are weighing heavy on your mind but only two you can solve at the moment. Take care of the two that you can so that you can clear your mind of them and now you are only facing three issues. Now lets say one of those can't be dealt with so you can take that off your list leaving only two issues to deal with. Now that you are not so overwhelmed you can focus on "thing 1" and "thing 2." You will then be able to clearly see how to get them done and you will be left with room for "peace of mind."