You've just received an invitation in the mail to a friend or loved one's wedding. Now what? What can you do to be a gracious guest and still have a good time?

RSVP

RSVP within three weeks of receiving your invitation even if the deadline is still far in the future. Not only is this considered good manners, but it prevents you from forgetting or losing the invitation.

Check your schedule before you respond. If something comes up and you must cancel, do so as far in advance as possible.

Gifts

You have up to one year to send a gift, although if you wait longer than two months the couple may think you've forgotten. Gifts do not have to be taken to the reception. Instead they can be sent in advance to the couple's home.

A gift is expected even if you cannot attend the wedding.

If you don't know where the couple is registered, check the couple's wedding website or ask.

Guests

If the invitation doesn't say "plus guest," that means you can't bring a date. Don't pencil a date in on your RSVP card or bring a guest anyway. Worse, don't beg the couple to be able to bring a guest. The only exception to this rule is if you are cohabitating, engaged or married and your significant other wasn't included. In that case, it was an oversight on the couple's part.

By the same token, if your children's names aren't included on the invitation, then they aren't invited to the wedding.

Attire

The wedding invitation should imply formal or informal the wedding will be. Dress accordingly. For formal weddings, even those held during the day, black tie is acceptable. Only tails are still considered evening attire.

Never wear white to a wedding and never dress to complete with the bride.

Ceremony and Reception

Allow yourself plenty of extra time and don't be late. You don't want to arrive just as the bride is walking down the aisle.

Don't compete with the professional photographer when taking photos. Better yet, don't take any photos at all during the ceremony, especially a religious one.

If you're invited to both the ceremony and reception, don't just show up at the reception. Remember the ceremony is the most important part of the whole day.

Respect the couple and sit only at your assigned table. Don't give a toast unless you were asked in advance.

It's considered bad luck not to take a bite of wedding cake. You can leave any time after the cake has been cut.

And Some Don'ts

Don't disrespect the couple's wedding traditions. Stay quiet during the ceremony and take your lead from the congregation.

If you're also planning a wedding, refrain from talking about your plans. This isn't a completion.

Control your alcohol. No one wants to be the guest who embarrassed himself or caused a disruption.

Finally, stay off your phone during both the ceremony and reception. Any phone calls, checking voicemail, text messages, Tweets and Facebook posts can wait. The wedding is all about the happy couple.