Stand up straight.

"Posture influences how qualified you consider yourself."

An Ohio State study told respondents that they'd be participating in two studies, one for the arts school and one for the business school. The arts study, they were told, gauged posture's influence on other activities. They were then seated upright, slouching forward or slouching dramatically downward, as they participated in a business study on professional performance. Students sitting up straight were much more confident about their own self-analyses while students in the slumped-over position seemed unconvinced by their own thoughts, and their self-analyses were insincere and doubtful.