How you explain setbacks to yourself and how you interpret a situation determines negative or helpless ways of thinking. For example, your boss is critical of a presentation, and your negative thinking takes over. I'm a failure at this. I will never get promoted. Negative thinking can become so automatic that you may not even be aware of your style.
Awareness is the first step.
Get the facts. It's important to be honest when you run into a setback, but in most cases, it is not a catastrophe. Be accurate and candid in your assessment of what has happened, and keep things in perspective. Act, don't react. Before rushing to judgment in a stressful situation, take the time to evaluate the situation before you overreact.