Memories are the byproduct of the vibration you maintain. Therefore, as your personal vibration changes, so changes the nature of the memories to which you have access. Thus, with your every thought you are creating memories in that every one of your thoughts define the nature of your vibration and thus also define the nature of the memories that are thereby formed.
This information may be utilized by taking full advantage of your ability to define the nature of your vibration in the present by deliberately choosing your thoughts. As you think a thought of a certain nature, your vibration will immediately become more alike in nature to the thought being considered and thus so will the memories which you may access in that particular moment. Ergo, the more desirable are the thoughts you think in the present, the more desirable will become the memories which you are able to recall.
In this way, you may actually gauge the desirability of the thoughts you are thinking in any given moment, since the desirability of the memories that arise within your mind are typically of an equal desirability to the thoughts you are thinking. As the memories that naturally pop into your mind increase in desirability, you can be certain the desirability of the thoughts you are choosing are also improving to an equal degree.
Another way of looking at this effect is that of viewing each thought as a potential future memory. Your choice of thought now will produce various experiences that will soon be remembered in the form of memories from a future perspective. To make the most of this effect, you can make the thoughts you think now as desirable as possible so that the memories that are recalled in the future will be of an equal desirability.