To have wisdom is to avoid all thoughts that weaken you.Dr. Wayne Dyer
Don’t try to suppress your negative thoughts.
That would be too much effort and, since they come and go randomly, we might feel as if we have “failed” if they keep coming back – the exact opposite of what we want to achieve.
Instead, simply add positive thoughts and replace the negative thoughts. In your head there is always only room for one thought – the negative one gets pushed away automatically when you chose a good thought in its place.