By paying attention to David and Goliath's conversation, you realize something very important. From verses 43-47 David mentions his God 6 times and his giant twice. This means that David was focused on his God and not on his giant. Realize in the big problem you have now how much time you give to your problem. How much do you talk about your problem? How much do you focus on your problem? I did a test on one occasion where he is writing something and I started to review how much I talked about my problems and how many times I talked about God.