The nature of reality at its most fundamental level is a set of energy values in the form of vibrations of various frequencies. The result of this structure of reality is that anyone may easily alter its nature simply by introducing a vibration that differs from the current vibration of reality. As a certain vibration is introduced into reality, the vibration being introduced and the vibration of reality then become intermixed thereby resulting in a vibration that is of the average frequency of the two vibrations.
Therefore, the more extensively is a certain vibration introduced to reality, the greater does the likeness of the reality being effected become to the vibration being introduced since each additional introduction of the vibration results in the average frequency becoming more alike in nature to the vibration being introduced.
The key here though is the process of introducing the right vibration. The vibration you want to introduce is the vibration that matches your desire being a reality. Thus, the thought that produces such a vibration is that of the desire already being a reality.
For this reason, the best thought to introduce to your reality, if you wish to make it more alike in nature to your desire, is that of the belief that your desire is indeed already a reality. In other words, believe it to be true and then it must be true. The greater is your belief in something being true, the more alike in nature does your reality become to that particular truth. In the moment you begin to believe that the reality is indeed already in the desired state, its vibration immediately begins to match it and thus that which is believed to be true will then become true.