This is a very important step in your healing journey, the decision to "let go" of all negativity. I made the same decision once, telling myself that from this moment on, I would only acknowledge positive thoughts, that my outward actions would only be positive. How do you handle negative thoughts? When you notice them do not give them importance, shrug them off and then just "let them go" replacing them with positive thoughts. The emotional freedom technique (EFT) will also help you during this process.