I have never really studied Keswick Theology, though I was familiar with the general tenets. Then two situations arose that drove me to dig into the topic. First, a former student approached me expressing his frustration with his spiritual growth. He indicated that he was praying and praying for a breakthrough type of experience, where following Christ would become much easier and more joyful. Second, my wife went to a conference by Martha Peace where she was warned about modern proponents of Keswick Theology. She came back and asked me about it. So, what steps did I take to study it?
here. He also did a lecture series at Detroit Baptist Theological Seminary. You can listen to the audio and follow along with his PowerPoint slides. It is available here. It is also available in written form.
These lectures are immensely helpful at describing how this theology formed historically, who proponents were, and the dangers of it. I believe that remnants of Keswickian thinking continues on and it props its head in many sermons, unbeknownst to the preacher/teacher. I urge you to listen to his lectures so you too can learn more about progressive sanctification and avoid falling for the Keswickian trap.
If you want to hear how the concept of "Let go and let God" almost destroyed J. I. Packer's spiritual life, read this excerpt.