In reply to Nadir khan: I'd recommend David hobby's lighting video seminar. Not only is the strobist content second to none but you get to watch him direct his models on shoot. After watching him you'll never feel self conscious about directing, his patter with his subjects borders on ridiculous but it gets results.
Helped me anyway
"look like you own me, yeh hold that, hold that great" etc
Of course another useful insight is the documentary film Zoolander