Receive a positive, motivational message like this every day in your email. We feel that we have to do something perfectly the very first time. In reality, the only way to even approach perfection is through practice and experience. Highly successful musicians, professional golfers, public speakers, surgeons and others who have mastered a particular discipline, know the value of experience. And experience consists largely of past mistakes.
Mistakes are excellent teachers.
They're nothing to be afraid of. Of course anything worth doing is worth doing right. There's nothing wrong with having mastery as your goal. But if you're ever going to get anything done, you must start somewhere. Give it your best shot and learn from the experience.