Good Gifting
DO provide the happy couple with a gift -- no matter what. However, you needn't bring one to the reception if you sent one ahead of time in the mail. Only one gift is required.
DO politely follow up after six weeks to make sure the couple received your gift if you haven't received a thank-you note by then. You want to make sure the present arrived on time and in good condition.
DON'T ask the bride and groom at the reception whether they liked your gift. It will sound like you're "fishing," and will put the focus on you when it should be on them. It also puts the bride or groom on the spot. Out of fifty, one hundred, or more guests, it will probably be difficult for them to remember which gift was yours.
Greeting the New Couple
DO wait your turn in the receiving line before entering the reception hall. DON'T go on ahead without being formally received by the bride and groom, unless there is some emergency or you have extenuating circumstances (for instance, you are in a wheelchair and there are only steps rather than a ramp).
DO allow seniors or differently-abled individuals ahead of you in line. This isn't a must, but it will make a good impression and is general good etiquette.
DO say "congratulations" to the groom and "good luck" to the bride. This is an ages-old social must.
Good Eats
DON'T begin eating until the best man or other appointed person has made the first toast.
DO observe good cutlery etiquette. (This is an easy one -- work from the outside in, and never re-use the same piece of cutlery for the next course.)
DO tell the bride well ahead of time if you have any special dietary considerations. DON'T wait until the actual reception to do this; it will throw a monkey wrench into the kitchen's plans and could send the already stressed bride into a tizzy. Be reasonable; if it's a preference and not a serious medical concern, let it go. Push the salty garlic mashed potatoes to the side and nibble on the asparagus tips instead.
Wait Your Turn
DON'T interrupt the bride or groom while he or she is speaking with someone else.
DO wait for the couple to come around to your table before getting up to offer congratulations and a few words. Generally, the couple will do a quick sweep of all the tables in the room to make sure they haven't missed anyone. After you're sure the couple has gone around the room at least once, you can then go over for a more informal chat with either.
And a Good Time Was Had by All
DO make sure you seek out the bride and groom (individually, if they're not together at the time) to thank them before leaving the reception. This is an absolute etiquette must, even if you are on close terms with the couple or have spent a good portion of the evening talking to them.
The next time you see the bride in a more informal setting, DON'T complain about the reception -- no matter what. Unless you are a direct family member (mother or sister, for example) or the bride's best friend, no bride wants to spend $75 a plate only to hear later that the air conditioning was frigid or the lemon cod was too dry. Simply smile, tell the bride again how much you enjoyed sharing her special day with her, and go on your way.
Use these etiquette tips, and you'll be a guest that's welcome at any wedding reception.