Everyone should want to build rapport during a handshake. One essential component of such a influencing handshake, is having the palms and fingers oriented vertically (perpendicular to floor). Much too often, the person who is perceived as more alpha orients their hand on top - in a dominance display. Although there are occasions for this, they are relatively uncommon to rare. If you're trying to win votes, you want people to perceive you as "one of them" - as an equal. Thus this hand orientation is particularly important. Of course, this nonverbal is also just as instrumental if you're a sales person, CEO, attorney, physician, clergy or in any other non-elected position of leadership. In this image Mitt Romney shakes hands with supporters in Jacksonville, just prior to winning the 2012 Florida Primary.