Prayer is one of the most powerful defensive (and offensive) weapons in the full armor of God that Jesus has left with us. Before He left this earth He repeatedly urged the disciples to watch and pray. Jesus knows the power of prayer and prays all the time. He still prays (intercedes) for Christians while sitting at the right hand of God today. (Romans 8:34)
I have found many good teachings on prayers over many years. I have learned from them and been transformed in my prayer life and living before God.
I put some of the good stuff on a plate now and hand to you: Here are some good prayer teaching resources from Andrew Wommack for Christians. I pray that readers will be encouraged to listen to them: http://www.awmi.net/audio/audio-teachings/#/awm_y03_kindsI.mp3
There are many more audio teachings on many essential topics on Christian living. Please visit the web site: http://www.awmi.net/audio/audio-teachings/