Your own way of thinking is a habit.
Like developing a good habit, you have to repeat your favorable way of thinking again and again—until it becomes part of your auto-pilot system.
On the other hand, if you want to remove an unfavorable way of thinking from the auto-pilot system, you have to repeatedly interrupt that thought pattern and redirect it to a better one. Or an ideal one. You have to work on this 24/7 because your brain keeps working even while you are sleeping.
I still struggle with removing my negative thought pattern. It often wakes me up at night and keeps me from going back to sleep for hours. I always feel like I’m decoding my auto-pilot system—it’s sometimes quite bothersome, but also helpful because I almost always find something I didn’t know about myself.