Here's a trite little piece from the Columbia Tribune where Joyce Hulett (PhD and educational expert) explains how to raise self confident kids in such simple terms it's astounding all kids don't grow up full to the brim with self confidence. Joyce touches on some key points, such as dishonest praise we may give kids when they haven't actually accomplished anything significant. Children can easily see through that praise and it can actually make them more insecure.
The rest of the article is full of empty advice like, "Too much self confidence can be a problem. Children can annoy other children if they display too much self confidence." Or, "Parents are responsible for seeing that their children are dependable and responsible. That means they must hold their children accountable for their actions."
So pretty much tell your kids you love them, give them honest praise when they succeed, teach them the golden rule and be a good role model. Ta-Da! Self confident kids. It all seems very obvious to me, but maybe Dr Hulett's advice will change your life.