It is important to be polite, friendly, and helpful to the family as soon as you arrive. Join in - do not go to your room and sit quietly waiting to be spoken to. Au pairs who use their initiative and make friends with the children are an immediate success!
Get clear instructions about what you are supposed to do and, if you are not sure, ask. You must behave reasonably and with respect for the family. When you arrive you will be given a guidance leaflet with more advice about how to make your stay a success.