Formal Attire: If you're confused about what's appropriate when it comes to formal wedding attire, you can never be too overdressed. When in doubt, a dark, well-tailored suit or a floor-length formal wedding guest dress are safe choices. But if you're feeling adventurous, you can experiment with trendy jumpsuits, a suit with a colorful jacket or bold accessories. As you're choosing what to wear to a formal wedding, remember that erring on the side of caution with a more formal look is always a safe choice.