Watch the The Dimension of Listening online guitar lesson by Steve Vai from Alien Guitar Secrets: Passion & Warfare
Entering the dimension of listening very carefully without thinking is something that you can do any time. When you're sitting around waiting for something is a great opportunity. It immediately brings you a sense of peace, too, because you're not in your head. It's an incredible thing to do, especially in nature. If you sit, you'd be surprised, that the deeper you listen the more you hear. I do this every night with my wife, we sit on the porch and just listen. There's a symphony going on at all times from every dimension and area. The more you listen, the deeper you get into it and the more fascinating it is.
It's also a great practice for being an effective musician. When you're writing music, what you're really doing is listening to your inner ear. When you're performing with someone and sharing the intimate space of creation, the depth of your ability to listen is going to be directly reflected in the quality and power of what you create with the other person. So, I would highly recommend alongside all the things you're learning to practice the dimension of listening even when you don't have an instrument.