Men greeting Men - Men usually shake hands when greeting one another.  A relatively firm handshake is the norm.  It is considered polite by many to allow elders or people in superior positions to extend their hands first.

Women greeting Women- At a first meeting, women generally shake hands.  Good friends and family often exchange a single kiss on the cheek. 

Greetings between Men & Women-   At a first meeting a regular handshake will do. Many times a simple nod of acknowledgment will suffice. It is considered polite by many to allow the woman to extend her hand first.  Good friends and family may exchange a single kiss on the cheek.