The codes change regularly and different social cliques or professional verticals distinguish themselves by them, so they can be hard to Define. When in doubt: don’t be a tourist.
Know how to pronounce the items on the international restaurant menu before trying to order them. If you don’t know, don’t ask out loud. Whisper into your rich friend’s ear so as to not embarrass them.
Don’t speak about the unspoken codes either, and if you must, do it privately with your rich friends and go along with their answers.
Don’t not have enough money for something unless you express clearly that you are too good for it. Not needing it bad enough is not an acceptable excuse.
When others share stories of their extravagant lives, hold a straight face. This is normal stuff for you, remember? You already know what that’s like.
Speak of politics as though identity issues(D) or working hard for your money(R) are more important than class issues. Remember that class issues are not something you are particularly affected by. You can acknowledge they matter but insist identity issues are more important. This helps wealthy folk feel both compassionate, concerned and comfortable with their wealth. I’m not taking a side here, only giving proven survival tips.
Your family is kind of more like cartoon characters. You just share jokes with them and nothing else, unless something tragic happens or if they invite you on a nice vacation. Don’t discuss any other relations with your family members.
Fashion: In the least, if you wore it in high school, you don’t wear it now.
Music, art: Don’t ask who this is. You’ve heard it or you are too busy to care.
Like parent said, these can be overridden with confidence and flair but that takes some acclimating and strategy.