Get a pen and piece of paper. Get a stop watch or something and time one minute and thirty seconds. Close your eyes. Relax yourself. Think deep into the back of your mind. When you're ready start the counter and let your thoughts run free. Write every thought that comes to mind in the form of a basic tag cloud. When the time is up, review your thoughts. If any of them are even remotely negative in any way, write a new word or phrase to describe it in a positive way, 3 times. Do this regularly and aim to fill the entire page with your thoughts as you repeat the exercise. The day you find that the page is full, and there isn't a single negative word or thought there... Set a higher bar, and apply it to your entire life, all your thoughts, always. Program your subconscious with this new program you've just mastered. Then you will start to see serious changes in your life.
Hrm. I should charge money for this stuff!