A fascinating line of research has looked at how body posture, specifically "power poses" can be used to build a sense of strength and confidence in social situations. The results suggest that a very simple strategy can increase your confidence in stressful situations such as job interviews, negotiations, or when meeting new people.
In a series of studies, psychologists Dana Carney, Amy Cuddy, and Andy Yap had participants hold either very expansive, high power postures (e.g., arms on hips, legs apart: the "Wonder Woman" pose; or seated with legs on desk and hands behind head; the "CEO" pose), or very closed positions (e.g., arms and legs tightly together). They then measured participants' sense of confidence, power, and took saliva samples to measure the hormones testosterone (the power/dominance hormone) and coritsol (the stress hormone). [Participants were wired up to phony electrodes and told that the postures, open and powerful, or closed and restricted, were needed to get better readings from the electrodes.]
The results showed that holding the power positions for two minutes or more led to greater feelings of power and confidence, with higher levels of the dominance hormone and lower levels of the stress hormone. Moreover, in subsequent studies, it was found that the power pose was also related to more risk-taking.