When guys first start out confidence will be gained by the actions that you take. The short term pain will turn into long term pleasure, so remember this and have the fortitude to push through.
Part of your confidence is reflected in your physical body and your style. To master your body, you should consult the body building knowledge of work. With style, I think it is so important to understand the basic principle Style Attraction Switches, which you can read about here.
David Wygant gives you some body language tips on coming across as confident and dominant:
Over time, as you take action, you will gain more and more confidence as you develop your skill set. For more information on the seduction community, checkout PUALingo.com