Young Grasshopper has the right idea. The only way that you and your group will get better is by beating him. Each game you will get better. you will minimize your mistakes and capitalize on his. This is how i became a better player. my friend would always crush me. his German juggernaut verses my pathetic red army. Now its pretty even every time Barbarossa happens, and its not just on one front. Its world wide i can stem his advance or cripple his force so much he has to think twice before attacking.
On top of that, try to play against multiple different players, either on this forum, or on TripleA. You can learn a lot of new and effective strategies.