It’s tough to figure out what’s right to wear to today’s weddings. Yes, there are rules, but some of those rules are made to be broken, or at least bent.
Almost every wedding falls into one of three categories: formal evening; semi formal/cocktail and informal/casual. Here’s a guide for you to find the right wedding wear.

If it’s a formal evening affair
Men have it easy: a tuxedo.
For women, a long dress is entirely suitable but not required. It is bad form for guests to draw attention away from the bride, so a low-cut, skin-tight sequined red discount aline wedding dresses, for instance, would not be a good choice. As a wedding guest, it’s not your job to stand out. That’s the bride’s job.

A semiformal/cocktail wedding
For men, it’s suits and ties. A dark suit is right for evening, but tan or seersucker is fine for day.
For women, pick a discount plus size wedding dress or suit but fancied up with jewelry so you don’t look as though you just came from the office. Evening calls for discount cocktail wedding dress, but a pantsuit is an option. Add some sparkle, sequins or rhinestones to amp your outfit.

The hardest one to get right. As a general rule: Better to be overdressed than underdressed.
Men might not want to hear this, but it would be nice if they wore a tie. It’s a sign of respect for the couple. Khakis or seersucker pants with a contrasting jacket are options. But if it’s a theme wedding, dress accordingly. Dressier leather sandals are a good option for the beach. Overall, take cues from the setting.
For women, even if the wedding is on a beach or in a meadow, showing lots of skin is not a good idea. What’s right? You have to infer based on location. On a beach, a long flowy skirt is great. You could even wear an embellished tank top. But in another setting, casual means Sunday best. For sure, wear flatties or sandals if you’re on sand or hiking up a hill. Can’t figure it out? It’s totally fine to ask.

A word about white: You may wear white, with caution. But, don’t even remotely approximate a wedding-type gown. Some brides will be enraged if you wear white. Others don’t care.