Portuguese polite habits aren’t very different from American customs, but there are some small things that help making new friends easier. People are very warm and relaxed, so any mistakes are never a big deal, as long as you remember your “please, and thank you” (Por favor, e obrigado!).
You’ll see many people greeting with two kisses on the cheek (mostly between women or men who haven’t seen each other for long) or hugging. This is for friends and family, so when meeting a person for the first time, the proper thing to do is a handshake.
At the table, things are a little different! People eat with the fork on the left hand and the knife on the right hand at all times. If you’re at a restaurant, for example, setting your fork and knife side by side lets the waiter know you’re done with your meal and he or she can take your plate away, so it’s important to notice how the cutlery is set down. On the other hand, crossing your cutlery is considered rude, but not very offensive.
In all situations, the best way to learn is pay attention to what other people are doing, and when in doubt, just ask. No one will be upset by questions, on the contrary, the Portuguese will love the chance to tell you about their culture and customs!