The continued repeated process of pushing the negative attitudes out of your mind with your personal power, and then repeating the new positive affirmations/visualizations into the subconscious mind, is the main key to reprogramming the subconscious mind.
The pushing out of your mind of the negative thought/image is like a plant that is not being watered. The negative thought/image is not getting energy, so it withers and dies. The continual, constant and repetitive use of positive thinking, affirmations and visualizations waters this new seed thought in the soil of your subconscious mind and it begins to grow. It is like a tape recorder that rerecords over an old tape recording.