Just because it's not your big day doesn't mean you don't have an important role to play. Here's how to avoid being that guest:
Reply as soon as you receive the invitation. "People are notorious for not responding, which really can be a hassle for the couple," says wedding expert Diann Valentine.
DON'T bring extra guests
Read the invitation carefully to see if you are allowed to ask additional guests to accompany you and if so how many. You should also determine beforehand if children are welcome.
DO be understanding
Give your girlfriend a pass if she's teetering toward Bridezilla territory. "Remember, it's not about you," Valentine encourages. "Your friend is getting married and she's excited, stressed and nervous. She may lean on the friendship more than she ever has before."
DON'T show out
From choosing your clothes to getting another cocktail, make sure to play it safe. This day is to witness two people join their lives, and not your time to shine. Steer clear of wearing white or loud colors to avoid competing with the bride. "Be mindful of the location, and bring a shawl if you are in a church," Bartlett-Royall says.
DO check their Twitter rules
Look for signs at the wedding or ask the couple's wishes on sharing. Some newlyweds ask guests not to post or to wait a few weeks before doing so, while others encourage posting to their own hashtag.
DON'T bring a big gift
Yes, you should give the bride and groom a present, but if you decide to purchase a large item from their registry, have it delivered instead of bringing it to the ceremony.