When you talk to Americans,you should notice these rules.
First,you should say Hi,and express you are kind.And if you want to start a conversation,you can start with weather.You'd better not to ask the age ,the address,the family background or something personal,if you want to know,wait for his speaking,that means when he would talk about that with you and you will know,or just wait until you are good friends.You can also talk about the movies ,the fashions and so on.