The best way to cleanse the heart and prepare for the stilling of the mind is to lead a normal, worldly life. Living in the midst of your day-to-day duties, responsibilities, likes, dislikes, etc., will help you. All these become the very means for the purification of your heart.
If you are convinced of God's existence then it rests with you to seek Him, to see Him and to realize Him. Do not search for God outside of you. God can only be found within you, for His only abode is the heart.
The book that I shall make people read is the book of the heart, which holds the key to the mystery of life.