Your thoughts create your reality. I'm constantly in awe by how many people don't know this (I guess that's why it's called The Secret). Overcoming your negative thoughts is the only way to live a positive life. How does one overcome negative thoughts? By being mindful of your thoughts. When you recognize that you've just had a negative thought, simply erase it by transforming it to a positive thought. Sure, easier said than done with you first start to become a mindful person, but as with all patterns and practices, it eventually becomes second nature.