The Universe is comprised of energy. This energy exists in the form of vibrations. Vibrations are also perceived in the form of emotions. Being that the world around you is comprised of vibrations, and your emotions indicate the state of your personal vibration, the nature of the Universe in which you exist is indicated by your emotional state. Ergo, as your emotional state changes, so changes the state of the world around you, and the more desirable is the emotion being experienced, the more desirable is the Universe in which you live.
In this sense, your reality becomes your emotional state, and the more desirable is the emotional state you are experiencing, the more desirable is the reality then being experienced. Therefore, as you experience various emotions, you are really experiencing various states of reality, and as your attention is given to any particular emotion, you are then experiencing a state of a reality. And the more extensively is your attention given to that emotion, the more extensively is that state of reality then being experienced. Thus, if you wish to experience a certain state of reality, all that you must do is give your attention to thoughts that produce the emotion which corresponds with it, and the more is this done, the more extensively will you then experience that state of reality in the form of the emotion that matches it.