Meditation on the guru, the practice of guru yoga, is really the key to the successful and authentic practice of all dharma. Most especially in the uncommon and supreme path of dzokchen, it is the very essence and the genuine means of attainment. In fact, the only way to actually realize dzokchen and to meditate on it authentically is through cultivating devotion to your root guru and then mixing your mind with his by dissolving him into you. Dzokchen is a profound and quick path, one that brings the attainment of great unity in one life and one body. However, the authenticity of that path — that is to say, the correction of errors and sidetracks and the actual development of progress on that path — depend chiefly on devotion to the guru and not on the specific techniques of the path itself. Through devotion to the guru and through mixing your mind with the mind of your guru, all necessary corrections and enhancements will occur spontaneously.
[ From Ngondro Instructions for Practices in the Termas of Terchen Barway Dorje by Lama Tashi Topgyal.]