Weddings can be stressful as all hell—and you don't even have to be the groom.

The questions start popping up the minute you tear open that glitter bomb of an invitation: Can you bring the girl you've been dating for a few months? Should you bring the girl you've been dating for a few months? Do you book your flight early, or wait and see if there are last-minute deals? What does "semi-formal dress attire" even mean?!?

Take a breath, man. You and millions of other men have all been there. And millions more will go on to have the same questions and dilemmas.

That's why we talked to San Francisco-based wedding and events planner Morgan Doan of Morgan Events and Kristen Maxwell Cooper, executive editor of popular wedding-planning site The Knot, to find out what a guy needs to do to be the coolest, most stress-free guest at any wedding. Consider this your cheat sheet.

Be prepared and plan ahead

This might seem obvious, but the first thing you should do upon receiving a wedding invitation is decide whether you're going or not. "Many guests receive the invitation and forget to RSVP while they're making plans," Maxwell Cooper says. "RSVP early. It makes the [wedding] couple's job so much easier."

Once you've mailed the RSVP, make any necessary travel plans early. Maxwell Cooper suggests booking the hotel first so you can take advantage of the couple's hotel block, which will offer you a discounted rate on rooms.

This is especially important if it's a destination wedding. "Destination weddings often involve multiple events, such as a welcome party, an after-wedding brunch, and maybe even the rehearsal dinner," she explains. "The couple chose that specific hotel for a reason, and a lot of the events will probably be at or near it."

If it's a destination wedding, consider arriving at least one day before the first event, so you can get acclimated to the local climate and/or a different time zone, Doan says.

How to decode a wedding's dress code

Guys have fewer style options, so there's less of a chance you'll screw this up. But there are still plenty of grey areas in the terminology to leave you floundering. Here are the most common dress codes you'll encounter on a wedding invitation, and what you'll be expected to wear. (Pro tip: Get in suit-wearing shape with our wedding workout.)

- "Black tie"
For the most part, this is the most formal dress code you'll come across on an invitation, and it's usually reserved for evening events. In the American South, black tie can also imply a white tuxedo jacket with black pants. You're unlikely to come across the even-more-formal "white tie" dress code (unless it's a royal wedding), but if you do you'll need to step it up with a tailcoat, waistcoat, white bow tie, and the optional gloves, cane, and top hat.
What to wear to a black-tie wedding: Unless otherwise indicated, a tuxedo with a black bow tie, cummerbund, and polished black Oxford shoes. (Patent leather shoes are optional.)

- "Black tie optional"
This is one step down from black tie, and means a tux isn't required—though you won't look out of place if you want to wear one.
What to wear to a black-tie-optional wedding: A formal, dark-colored (black, navy, or dark gray) suit and tie, or a tuxedo.

- "Resort/beach formal"
It's a beach wedding, but it's still sort of formal. "Think casual and breezy, but still dressy," Doan says. "Opt for light neutrals paired with bright, sunny colors: Khaki and shades of white and ivory with seafoam green, orange, bright pink, or yellow all look stunning near water."
What to wear to a formal beach wedding: A relaxed button-up shirt and rolled-up trousers in a light, breathable fabric like cotton or linen (you don't need a tie). Wear close-toed shoes (no flip-flops) like boat shoes or loafers. If you're angling for the "best dressed" award, you could go with a cotton or linen suit (no tie).

- "Semi-formal/casual"
Semi-formal can be tough to read, but a good rule of thumb is to look at the time it's being held.
What to wear to a semi-formal wedding: If the wedding is in the evening, play it safe with a more formal, dark-colored suit and tie. If the wedding is in the daytime, you can wear a suit in a lighter color (such as light gray or a royal blue) or a lighter fabric (like chambray) and a tie. Ties, too, are a good way to improve a suit's versatility—wear a more understated tie if you're erring on the side of formal, but wear something that pops if you're up for some more fun. Not sure? Pack both.

- "Casual"
Casual can mean just about anything at weddings, but Doan suggests going for business casual at a minimum. Don't wear jeans, shorts, or—for the love of all things holy—a tank top unless the invitation specifically states you can, she says.
What to wear to a casual wedding: Dress pants (such as khakis, wool pants, or linen pants) and a casual button-down shirt or polo. Tie optional.

- No dress code
No dress code on the invitation? The best thing to do is ask—but not the bride or groom, Maxwell Cooper says. Your first call should be to a member of the wedding party, such as the best man, a groomsman, or one of the bridesmaids. If you can't get in touch with any of them, or don't know any of them, try a close family member or fellow wedding attendee. The bride and groom should be your last resort—they have enough to plan.
What to wear to a wedding with no dress code: If you can't get in contact with anyone at all, you might still be able to read between the lines. Evening weddings are usually more formal, while daytime weddings are less so (if it's a late-afternoon event, go for more formal). For a spring or summer wedding, suits in lighter fabrics and brighter colors are usually acceptable, but for a fall or winter wedding, you'll probably want to stick with a wool suit in darker colors. 

As you might expect, it's better to be over-dressed than under-dressed, Doan says—you can always ditch the jacket or tie after the dance floor opens up. And while you're almost certainly not going to be mistaken for the bride, it's always better to steer away from wearing white.

5 wedding etiquette rules every man should follow

As a wedding guest, your main job is to have fun. It's a celebration with friends and family. But as with Thanksgiving dinner, Aunt Joanie's Fourth of July BBQ, and the annual family reunion, that celebration comes with a few common courtesies you should know:

1. Don't be late (or duck out too early)
Arrive at the venue about 30 minutes before the ceremony starts. Arriving late is rude (shocking, we know), so err on the side of being early. If you can't stay for the entire reception, Doan says it's best to wait until the couple cuts the cake before you head out. 

2. Don't be a wedding crasher
Don't bring a guest unless you're encouraged to do so. If your invitation only has one name on it, it's for you only—even if you're in a long-term relationship (or even married), Doan says. If the guest list seems extra-strict, it's probably due to venue capacity rather than the couple hating your partner. "Usually couples are considerate of inviting a spouse or partner, but it often comes down to how close they are to you and your partner," she says. "At the end of the day, you always have the right to decline the invite." 

3. Don't flake
Weddings are expensive, and each guest costs money. If you RSVP, do everything in your power to show up, because the couple has done a lot to accommodate you as a guest, Doan says. If there's an emergency and you can't make it, it's always better to contact the couple. "They may be a little upset at first, but they'll appreciate you contacted them instead of just not showing up," she explains. 

4. Don't bring physical gifts
If you're getting the couple a physical gift, it's better to ship it to their home instead of forcing them to lug it with them from the reception, Doan says. If you purchase something off their registry—which you should try to do ASAP, so they're not overwhelmed with an influx of gifts—it'll be shipped to them automatically. Envelope gifts, such as money or gift cards, can be given at the venue. 

If the couple asks you not to give gifts, Maxwell Cooper says you should respect their wishes but consider bringing a handwritten card. "If you buy a gift from the registry that was shipped to them, it's still a nice gesture to bring a card to the wedding," she says. 

Oh, and you might think being creative and shopping without the registry will get you brownie points, but it won't. The specific items the couple chose are there for a reason: They really, really want them. Forget the one-of-a-kind fish sculpture you found at a flea market. There's a fat chance your buddy (and a zero chance his soon-to-be wife) will cherish it...or put it in their new home together. New couples don't want random crap. They want functional, high-quality gifts that make their new lives easier or give sentimental value. Wouldn't you rather they think fondly of you when they toast with nice-as hell wine glasses or whip up their morning smoothie with a kickass blender? Of course.

One more thing: Unless circumstances dictate otherwise, a gift of cash is a perfectly acceptable option. No one's gonna argue with an influx of funds—especially not a young couple starting a new life together. Just get a nice card to go with that check.

5. Don't get drunk
Don't be the sloppy guy hitting on the bridesmaids, spilling champagne, and stepping on everyone's toes on the dance floor. Your favorite part about weddings might be the open bar, but the couple who's trying to make a memorable night doesn't need your shenanigans to outshine them.

Use these tips and guidelines to help you through any upcoming wedding snafus. After all, there's more to being a wedding guest than just showing up for the free food.