Study a single sutra by selecting the pada (chapter) and then the sutra (verse).
Source: English translation from Light on the Yoga Sutras of Patanjali (B.K.S. Iyengar)
Perfection in asana is reached only when effort ceases, instilling infinite poise and allowing the finite vehicle, the body, to merge in the seer.
Source: How to Know God: The Yoga Aphorisms of Patanjali (Swami Prabhavananda, Christopher Isherwood)
Posture becomes firm and relaxed through control of the natural tendencies of the body, and through meditation on the Infinite.
Source: English translation from The Heart of Yoga (T.K.V. Desikachar)
These qualities can be achieved by recognizing and observing the reactions of the body and the breath to the various postures that comprise asana practice. Once known, these reactions can be controlled step-by-step.
Source: English translation of the Yoga Sutras of Patanjali (Swami Jnaneshvara Bharati)
The means of perfecting the posture is that of relaxing or loosening of effort, and allowing attention to merge with endlessness, or the infinite.