Traditionally, most Vietnamese slightly bow when they meet each other. However, most Vietnamese living in the urban areas no longer bow.
In formal or religious occasions, some people make make prayer-like hand gesture and bow. This is not practiced to any extend in everyday life in Vietnam as it is in the country's neighbor, Thailand.
Children cross their arms and bow to show signs of respect to the elders.
Most Vietnamese go by their first name. A lot of times, after introduction of their name, Vietnamese ask for your age or your year of birth because they want to refer to you appropriately.
Handshaking has become more and more common due to the Western influences in the country. Some Vietnamese might give you a two-handed handshake. The showing of both hands is gesture that symbolizes respect and a lack of hidden agendas.
Initial greetings will often be accompanied by an invitation to a home or restaurant, either for a meal or a cup of rich Vietnamese coffee. Your Vietnamese acquaintances will readily invite you into their homes.... as long as you don't forget to take off their shoes before coming into the house. This is considered extremely impolite in Vietnamese culture.