The Worst Enemy to Creativity is Self-Doubt

In an interview with Clare Owen, an illustrator that I admire, she was asked what advice she would give to women starting out in the illustration field. She answered with this quote by Sylvia Plath: "And by the way, everything in life is writable about if you have the outgoing guts to do it, and the imagination to improvise. The worst enemy to creativity is self-doubt.” Clare went on to say, "For your best work, you have to be calm and confident. So try keep your head up and believe in what you do."

How do you get started when you're full of self-doubt or fear of failure or whatever you call it? I know I have my share of doubt and fear and excuses in general.