Just read this and found it quite interesting. I've found some of the tips work for me so maybe you will too.
http://www.positivityblog.com/index.php/2007/08/14/top-24-tips-for-making-your-self-confidence-soar/
http://www.positivityblog.com/index.php/2007/08/14/top-24-tips-for-making-your-self-confidence-soar/