Arms offer clues as to how open and receptive we are, so keep your arms to the side of your body. This shows you are not scared to take on whatever comes your way. Quieter people tend to move their arms away from their body less often than outgoing people, who use their arms with big movements.
Here are two common perceptions of hand gestures: 1. Palms slightly up and outward: open and friendly
2. Palm-down gestures: dominant and possibly aggressive