if you're doing to be a guest of an American,you should do your best to follow the rules below,so you'll be polite and nice.
First,you should buy the host a little gift,such as a qute cup or some flowers.A bottle of wine will be nice, too.
Second, please be on time! That's very important.Neither early nor late!
Third,when you have dinner with your host and qther guests,you must
show how you love to have the meal,and also you'd better prise the hostess about her cooking,that'll be good.
Fourth,don't stay too long at their home,and say thanks when you say goodbye to your host.