Round up your clothing. The invitation should have indicated whether the wedding is black tie, semiformal or informal; daytime or evening; indoors or outdoors. If it doesn't, ask the bride -- you don't want to be wearing an evening gown to a barbecue.
Pick colors and fabrics that won't show stains easily, in case your suitcase gets wet or damaged during travel.
Include at least one extra heavy-duty nonwire hanger in your suitcase. Some hotels don't provide hangers, and if you have time to let the outfit air out before the wedding, it's nice to let it naturally de-wrinkle.
Bring everything you need to get ready for a night out. For women, that might include makeup, brushes, a hairdryer and an evening bag to match your outfit; for the men, grooming kit, razor and shaving cream. Include an extra pair of stockings or socks.
Include clothing for other wedding-related events, but pack as lightly as possible. Formal clothing takes up more space than everyday wear, so budget room in your suitcase for everything.
Try things on the week before you leave, in case there are any last-minute alterations needed.
