You cannot go straight from Rajas or Tamas to Sattva. A Rajasic person needs to engage in Tamasic activities such as gentle yoga practices, silent meditation, alone time, to balance their character. A Tamasic person achieves harmony through physical exercise, dynamic meditation, time management.
To free yourself from the constant play of the Gunas, you have to first become aware of it. This is the role of asana, pranayama and meditation – to raise your awareness. Once you do, you naturally realize that situations in life are no more than a constant swinging between Sattva, Rajas, and Tamas.
You learn to respond according to each situation rather than reacting as if you have no control over your thoughts, words, and actions. Through awareness you begin to approach life in a Sattvic manner, led by your deep intuition on what is wrong and what is right.
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Ahimsa, non-violence.