There is a difference in knowing God and knowing about God. Most people know about God from things they have observed or heard. Your parents may have talked to you about God. You may attend church and hear sermons about God. However, knowing about God is not knowing God.
Know God by faith. "He who comes to God must believe" (Hebrews 11:6). You cannot come to God any other way. Because God is Spirit, you cannot see Him with your eyes (John 4:24). Only faith can usher you into the presence of God.
Know God in your heart. The word "heart" refers to the mind, will, and emotions. God changes your heart through the gospel of Jesus Christ. That's when you know God the Father through Christ the Son (John 14:6). Know God by "looking unto Jesus, the author and finisher of our faith" (Hebrews 12:2).
Know God through a personal relationship. Then, you can walk with God by faith. "For we walk by faith, not by sight" (2 Corinthians 5:7). Faith is the assurance that God is with you, and all the time. Faith is the assurance that God hears your prayers. Faith is the evidence. When you know God, "faith is the evidence of things not seen" (Hebrews 11:1).