First examine what is constantly there in your mind, what is being repeated again and again. You don't have many thoughts. If you examine minutely you will see that you have only a few thoughts repeated again and again -- maybe in new forms, new colors, new garments, new masks, but you have only a very few thoughts.
And if you go into it minutely you will be surprised: you have one basic thought.
Gurdjieff used to say to his disciples, "First find out your main characteristic." And each person has a main characteristic -- it may be greed, it may be anger, it may be sex, jealousy, it may be something else. Find out which is the main characteristic, which is the center around which all your thoughts and moods move. If you can find the center, you have found the root.
And the miracle is that once the root is found you need not cut it, it is cut in the very finding of it. This is the inner secret of transformation.