Focus on how you want things to be. Choose the words you use carefully. Express your self-talk statements in the present, even if you don't quite believe them yet. Challenging the negative or useless aspects of your thinking allows you to feel better and respond to situations in a more useful way.
You can practice noticing your own negative self-talk as it happens and consciously choose to think about the situation in a more realistic and useful way. You might be surprised to realize how distorted some of your previous thoughts were before. Free list of 101 positive thinking statements.