How to Eliminate negative thoughts
When an evil thought harasses the mind, the best method of conquering it is by ignoring it. How can we ignore an evil thought? By forgetting it. How can we forget? By not indulging in it again, and also by not brooding over it. How can we prevent the mind from indulging in it again or brooding over it? By thinking of something very interesting, something sublime and inspiring.
Ignoring, Forgetting, Thinking, of something inspiring, - these three constitute the great Sadhana for establishing mastery over evil thoughts.
~Swami Sivananda
