Who is God ?

Every one has his own God in his heart. What I understood after reading my holy book Quran that I have explained in this book. What is the meaning of love to God in reality ? How can we feel him and make him our friend by understanding him and ourselves as human beings have many soul(heart)diseases. We should cure them in the light of God´s knowledge and what is the right path which can make us peaceful, satisfied, happy and good natured human beings and will make us successful in this and the next life .