The Power of Positive Thinking

Hola Rascals,
Lately I've found myself more self-aware of negative thoughts I'm having.  Whether it's a situation with money, health, family, or work, I seem to have a lot of negative "energy".  I really think it is beginning to erode my relationships with friends and mow down my love life (or lack thereof).  However, being aware of this, I am attempting to train myself to think more positively.  When I catch myself having a negative thought I force myself to process through why the negative thought was wrong and make a positive thought.  It's working so far.  I feel a lot happier and am not getting so down.  What're your experiences with this?  Have you overcame something similar?  Lemme know!
-Bill