I found that moving amonst upper class social circles in the U.S. is much easier that it would be in European countries. In the states the only thing you have to do is dress the part and eat with manners. In Europe your accent, facial features, name, all could be strikes against you.
I'm not sure that it's really much different in the United States. In my experience, dress and table manners will only get one so far, surname and accent matter (especially in the South and New England), appearance and education matter everywhere, and in the highest circles, connections, breeding (did one grow up riding, sailing, or golfing or playing tennis before they were mass sports), etc.) and ancestry still count, believe it or not.
The humorist and satirist Florence King wrote a remarkable little book entitled WASP, Where is Thy Sting? about twenty years ago or so. Out of print, but I highly commend it to you, especially if there is a WASP side to your heritage. My arch-WASP Mother and I were almost literally rolling on the floor reading it, recognizing one relative or another in most of the caricatures.
I'm remined of the regional differences in the questions people ask a new acquaintance in a social setting:
On the West Coast: What are you into?, i.e. what are you interested in?
On the East Coast: What do you do?, i.e. how much money do you make?
In the South: Who are your people?, i.e. where are you from and is your background respectable?
Curious.