Tapping the side of your head (at the temple) with a finger means someone is smart or clever.
Keeping your hands in your pockets or arms crossed during conversations may be interpreted as disinterest or disrespectful.
Bending an arm and tapping the bottom of the elbow with the open palm of the other hand means someone is unreliable or untrustworthy.
Gliding the forefinger down the bridge of the nose a few times usually indicates that someone is cheap.