Our practice for the month of August is very simple and therefore profound- "that which is complicated is of man, that which is simple is divine." It takes at least 28 days to make or break a habit, so a full month of practice is sufficient practice time to change habits. The technique is simply to refuse to say out loud "I feel tired", or any other words to that effect. When we do think that thought or happen to forget and say it out loud, we will counter the thought and words with "I feel great!"
This technique is a practice of mindfulness, awareness and of redirecting focus. There will be times when the physical body will actually be tired and fatigued, yet if we tune in with sufficient sensitivity, mindfulness, we may discover a part of us which does indeed feel great simultaneously. This place in Tantra is called the Cave of the Heart, the place in the heart which is beyond all sorrow, all pain and certainly beyond mere fatigue. In this practice, we redirect our focus away from the part of us which feels tired and toward the part of us which feels great. That which we focus on will grow and flourish.
With enough regular practice of finding and dwelling in the place in the heart beyond all sorrow, the practice may expand to finding the place that does not experience anger, worry, sadness, guilt, fear, etc. ( Nirlipta) Experienced Yogis become happier not because their lives become perfect, but because they develop a place within of profound comfort and solace- safe harbor in which to weather the storms of life.
PS: Pranams to Dr. Wayne Dyer, who inspired this practice.