1. RSVP! The proper wedding etiquette is to answer the invitation immediately in the mode that is requested
response card, email, text message.
2. Answer on behalf of those whom it was addressed to
3. If addressed to a list of names, reply with those names listed of those attending
4. And show up! Nothing could be more rude than a no-show.
5. Make your own plans to get there, sort out your accomodation if it is a destination wedding.
6. Don’t show up if you have declined the invitation.
7. Don’t try to do a second rsvp just because your travel plans fell through and you have nothing better else to do.
8. If attending the wedding, bring a wedding present with a prior effort to determine the couple’s preferred choice of gift.
9. Depending on culture and tradition, wedding gifts can be accepted in various forms, e.g. registries, cash gifts. Even if you are not from the same culture, take on the couple’s wedding gift tradition.
See Sending a Wedding Gift Etiquette