See the link at the bottom to watch Hugh Ross' comments on the activities of God before the creation of the earth!
An interesting question that many Christians have wondered about is, what was God doing before He created the universe. Remember, God is an ETERNAL being who stands OUTSIDE of time / He's not bound by it - because HE created it. Time is but a tool to God. So, whether one believes that the universe is in the billions of years old (I do, and accept the nearly 14 billion-year-old estimate, based on many scientific evidences) or you believe in a young earth / universe (in the thousands of years old), either is truly irrelevant when it comes to the activities of an eternal God. We can only know what God has told us, and He begins what we know of His activities at the beginning of the creation of our universe. But as Scripture notes that God is always active and creative - whether in the physical or spiritual realms - and as we know He NEVER changes - it poses an interesting question as to what He did before the time of our universe? Do we live in the ONLY physical universe He ever made, or all of the rest of His creations in the spiritual realm? We cannot know the answers to these questions, but we can speculate. And we know from our own universe, that whatever God creates, it must be stunning, beautiful, and beyond what we might imagine.
One of the few things we know about what God may have created before He created our world, is that He had already had created the angels:
Job 38: “Where were you when I laid the foundation of the earth? Tell me, if you have understanding. 5 Who determined its measurements—surely you know! Or who stretched the line upon it? 6 On what were its bases sunk or who laid its cornerstone, 7 when the morning stars sang together and all the sons of God shouted for joy?" ("Morning stars" has been interpreted to be angels. And there are various theological views about the reference to "sons of God - note, this is not referring to a Son like Jesus (Who is also fully God and a Person within His Trinity).
While we don't know much about what God did before He began the Creation, we DO know that He never changes and is ALWAYS at work. (John 5:17)
Here, Hugh Ross offers some insightful commentary and speculation upon God's activities BEFORE His creation of our world and universe: https://www.youtube.com/watch?v=TKJGPu3xUZs