I have begun a sermon series entitled, 'The God Whom We Worship'. I began with the truth that we only know as much about God as He has chosen to reveal. I also discussed archetypal knowledge and ectypal knowledge. The first is the knowledge that God alone possesses. He has perfect knowledge of Himself. The second is the knowledge that we have -- revealed knowledge. Though we are made in God's image we are not on the same plane with God(remember geometry?). Indeed mankind is on a separate and unequal plane from God. We can only know Him insofar as He reveals himself to us through general revelation (the knowledge of God in our heart as well as that which comes from creation) and special revelation (the Scriptures).
Compounding our ability to know God, and thus worship Him correctly, is the matter of human sin. I found the following quote very helpful with regard to God's revelation in light of Creation, Fall and Redemption:
"As a result of the entrance of sin into the world, the handwriting of God in nature is greatly obscured, and is in some of the most important matters rather dim and illegible. Moreover, man is stricken with spiritual blindness, and is thus deprived of the ability to read aright what God had originally plainly written in the works of creation. In order to remedy the matter and to prevent the frustration of His purpose, God did two things. In His supernatural revelation He republished the truths of natural revelation, cleared them of misconception, interpreted them with a view to the present needs of man, and thus incorporated them in His supernatural revelation of redemption. And in addition to that He provided a cure for the spiritual blindness of man in the work of regeneration and sanctification, including spiritual illumination, and thus enabled man once more to obtain true knowledge of God, the knowledge that carries with it the assurance of eternal life."
Louis Berkhof, Systematic Theology, p. 38. Eerdmans, 1938 reprinted in 1993.