I stumbled upon this video couple days ago. It's a 20 minute video but it's really flowing and fun to watch.
It's about reshaping your body language before you go into stressful situations. By reshaping your body language, your testosterone levels will go up, thus you'll feel more confident and powerful. Enough said, just watch it and you'll thank me later.
Amy Cuddy: Your body language shapes who you are | Video on TED.com