You have the potential to be your greatest nemesis, by what you tell yourself in your inner dialog. You can beat yourself up, tell yourself any number of reasons why something won't work or why you, of all people, can't pull it off, and why Murphy's Law is always at work in your life.
Many of us play these tapes over and over. We let the message sink in deep and take over our thinking. Personal growth is difficult at best. Ironically, we have the same potential to listen to a positive, upbeat message.
We can understand that the past does not predict the future, that every day is a new day, that you have just as much right to success as the next guy, and that Murphy is as much a myth as any of the other negative things we tell ourselves.
One of the mistakes people make when it comes to "positive thinking" is to believe that it's merely reciting some positive statements and trying to pretend everything is okay. The much tougher aspect of it is controlling this urge to listen to the negative inner conversation.
Turn your negative feedback into positive by...
Dismissing the negative self-talk as lies.
Reminding yourself of your previous accomplishments.
Reading and listening to positive material (Scripture, success stories).
Setting new goals that keep you focused on what's ahead, not what went wrong in the past.
It's one of the most difficult things to do, yet it's pretty simple: we must turn our inner critic into our inner fan.