All the above means of concentration are applied together. In the beginning, of course, it is difficult to imagine how one can focus on something rather than a posture itself. Start practicing dristis, bandhas and ujjayi in Surya Namaskara and genuinely try to perfect them. In Ashtanga Yoga tradition it is the concentration of your attention which is important, rather than performance of asanas. Be patient when focusing your gaze, holding locks and breathing ujjayi and you will realize that in your head there is no room for thoughts about daily life, life outside the mat.