The great paradox about surrender—as with other qualities of awakened consciousness, such as love, compassion, and detachment—is that though we can practice it, invoke it, or open up to it, we can't actually make it happen. In other words, just as the practice of being loving is different from being in love, so the practice of surrendering is not the same as the state of being surrendered.
As a practice, surrender is an antidote to the frustration that shows up whenever you try to control the uncontrollable. There are any number of ways to practice surrender—from softening your belly to consciously opening yourself to grace, turning over a situation to the universe or to God, or deliberately letting go of your attachment to an outcome. At the very least, the intention to surrender will allow you to release some of the invisible tension caused by fear and desire.
When the great will opens inside you, it's like going through the door that leads beyond limitation. You wonder why you didn't just let go in the first place. Then, like a surfer on a wave, you let the energy take you where it knows you're meant to go.