Upon introductions and departures, shake hands with everyone individually in a group; the American "group wave" will not be appreciated. It is polite while doing this to say "buon giorno" [in the morning] and "buona sera" [in the late afternoon and evening].
Frequent warm and vigorous handshakes can be common for both business and social occasions.
Italians will not hesitate to greet people they know with an embrace.
You'll notice that the Italians are often very animated and like to gesture with their hands while talking. In most cases, they gesture good-naturedly to emphasize a point or feeling.
While passionate gestures are common among Italians, they would not expect someone from another culture to do the same. When you know your Italian colleague well, it would be considered friendly to return a warm embrace.
Upon your arrival, it is considered common courtesy to greet people in the workplace, stores or restaurants with an appropriate daily greeting such as "buon giorno" or "buona sera" and "arrivaderci" upon leaving.