Italy is a surprisingly formal society; the following tips will help you avoid any awkward moments.
Greetings Shake hands and say buongiorno (good day) or buonasera (good evening) to strangers; kiss both cheeks and say come stai? (how are you?) for friends. Use Lei (you) in polite company; use tu (you) with friends and children. Only use first names if invited.
Asking for help Say mi scusi (excuse me) to attract attention; use permesso (permission) when you want to pass by in a crowded space.
Eating and drinking When dining in an Italian home, bring wine or a small gift of dolci (sweets) from a local pasticceria (pastry shop). Let your host lead when sitting and starting the meal.
Gestures Maintain eye contact during conversation and when toasting.