If you are going to achieve excellence in big things, you develop the habit in little matters. Excellence is not an exception, it is a prevailing attitude.
If you've got an idea, start today. There's no better time than now to get going. That doesn't mean quit your job and jump into your idea 100% from day one.
People are always blaming their circumstances for what they are, the people who get on in the world are the people who get up and look for the circumstances.