If anyone's looking to purify their mind a good place to start would be to study Buddhist vipassana
http://www.tipitaka.org/stp-pali-eng-parallel
We all visit heaven in our dreams that's why they all seem so real.
I read recently that before Buddhist go to bed they deaden their senses by covering their eyes with cloth or night mask, covering their ears with noise cancelling headphones like Bose and deaden their body by taking cold showers or taking short walks in the cold. Doing this makes your dreams or visits to heaven more vivid.
Exposition of the Truth of the Path
And what, monks, is the Noble Truth of the Path Leading to the Cessation of Suffering? It is this, the Noble Eightfold Path, namely: right understanding, right thought, right speech, right action, right livelihood, right effort, right awareness and right concentration.
And what, monks, is Right Understanding? It is this, monks: the knowledge of suffering, the knowledge of the arising of suffering, the knowledge of the cessation of suffering, the knowledge of the path leading to the cessation of suffering. This, monks, is called Right Understanding.
And what, monks, is Right Thought? Thoughts of renunciation, thoughts that are free from aversion and thoughts that are free from violence. This, monks, is called Right Thought.
And what, monks, is Right Speech? Abstaining from lying, abstaining from slander and backbiting, abstaining from harsh words and abstaining from frivolous talk. This, monks, is called Right Speech.
And what, monks, is Right Action? Abstaining from killing, abstaining from taking what has not been given and abstaining from sexual misconduct. This, monks, is called Right Action.