Every second you spend thinking about what you don't want in your life is a second denying focus and energy from getting what you do want. Every minute you worry about what's not working is a minute drawn away from creating what will work. And every hour spent reflecting on the disappointments of the past is an hour stolen from seeing the possibilities that your future holds.
What I've discovered in my own life is that I see more of what I look for. Clarity precedes mastery (big idea there) and the more clearly I look for what I want, the more powerfully I generate that result in my life. By setting clear goals in the important areas, I see more of what I'm searching for. By looking for the best in others, I generally find it. And by looking for the good things in my life and expressing gratitude for my blessings (rather than thinking about any problems), I see more of what's good.
Your thinking will create your reality. Your thoughts form your world? Why? Because you will never act against your thinking. Every action is the offspring of a thought. And your actions create the professional and personal life you find yourself in today.