In social situations, men shake hands and women kiss.
In Madeira, when gathering with friends on the street, at home or wherever, women kiss each other on the face (usually one kiss on each side of the face) and we also kiss men that way, if we’re friend or have already met in a friendly informal situation.
This is usually easy if you’re Latin, but English or German people are not used to it and might think we are being too familiar. We do it quite often, though, so don’t take it wrong if someone greets you with two kisses on the face. It will mean you’ve been included in the friendly circle.