I didn't realize how stressful planning a wedding is until I was planning mine. Emotions run high, bank accounts run low and time keeps ticking down while your to-do list goes up. The last thing you need is a crappy wedding guest.
We've all been guilty of being a sucky guest at one time or another (myself included) but here is a sure-fire way to never be that person again.
When you get a wedding invitation there is a date to respond by -- don't go by that date. Respond as soon as you open the invitation unless, for some reason, you don't know if you can make it. Everything hedges on the guest count: food, centerpieces, table configurations etc. The sooner you get the response in the better. I will forever hold dear my friends Natalie and Corey for being my first RSVPs.
Send your response card! Don't verbally tell the bride or groom you're coming. That's rude and unhelpful. They have enough on their minds and don't need to be mentally tabulating the people who "say" they're coming. Commit, send the card and PLEASE don't make them chase you down after the RSVP date has come and gone. They care enough to invite you to their wedding, care enough to mail something back that they've already stamped for you.
If you're not invited with a plus one, don't assume you can bring one, ask to bring one or pout because you can't. People are money in wedding world and one more person here or there means cutting corners elsewhere. Asking or writing in "and guest" on your response card puts the couple in a terrible position. This night isn't about you and the rando you're dating or your need to have someone to slow dance with. If you loathe the idea of going stag to the wedding, politely decline the invitation.
GIVE A GIFT NO MATTER WHAT
Whether you're attending the wedding or not, send a gift. Your newlywed friends aren't greedy gift grubbing a-holes for expecting something from their invited guests. Even if their parents are paying, all couples end up shelling out a ton of cash and odds are they don't have enough money for new sheets or a new frying pan. If you can't afford a nice gift or something on their registry then send a gift card or a nice bottle of wine. Anything works if it lets them know that you care about this massive step they're taking in their lives.
IGNORE THE ONE YEAR RULE
If you wait to send a gift or a card for the etiquette allowed 'one year,' your friends will think you're thoughtless and rude (obviously, if you have financial issues they will understand). Particularly if you missed their wedding or (the worst thing you could possibly do) if you said you were coming and no-showed after they paid for your plate you need to send something ASAP. A lot of time, effort and money go into planning a wedding. Flaking and not sending a gift really tells them you give zero f**cks about their marriage and, frankly, them.
Trust me, every bride and groom remembers the terrible guests and the ones who were shining stars. Don't forget, these people are your family & friends and you may need them for bail money one of these days.