In every human being, there are two forces – the good and the bad. With regards to thoughts, the Positive and the Negative thoughts.
You cannot stop the occurrence of Negative Thoughts in you but you should develop the ability to manage the Negative Thoughts. Disapprove it immediately.
We are in this world essentially to manage diversity and in the course of doing so, we compete with one another. The thoughts could come to you to destroy the opposition, you should immediately guide yourself against it. Compete positively and not negatively.
You could also have Negative Thoughts against yourself like bad thing flying past your mind particularly when you are about to sleep or sleeping, you should immediately seek protection of The Soul Maker against it by wiping your head with water or blowing air in your hand and wipe your head with it and say the general supplications. Praise and Glory to The Soul Maker. Let your Praise Be. I seek your protection against this thought. Let your Praise Be. Or something similar.