An action is first a thought in your head. Then a parallel thought gets initiated in your mind that decides whether you should apply this thought and turn it into an action or not. If the second thought gets verified, you start your action. And here lies the trigger, the second thought that gets initiated, it's always inspired by something positive or something negative. And it's so fragile that it gets affected by its surroundings. Here comes your job to control that second thought. All you've got to do is to get it stronger and let it be independent of the positives or negatives it might receive. You should let it decide for itself. And as a start, you might learn it by experience. That could be done by not giving it a chance to be initiated and you go on applying all the thoughts that pop into your head at once. Use the technique of do-it-now-or-never and don't worry, there will always be a feedback loop that feeds the experience's lessons to your mind for the next time you let your mind initiate that decision making thought. Then until you prepare your decisions to be independent, keep your mind open to experiences. You'll learn.
--Now, that is when a control engineer tries to speak! Hope you understand. ;)