When attending a Gurudwara wedding as a guest, dress modestly with clothing that covers your shoulders and legs, opting for floor-length dresses or long pants with a loose top, and remember to bring a head scarf to cover your head as it's customary to do so within a Sikh place of worship; avoid revealing clothing, and tight fits; bright colors are encouraged, but avoid black and white which can be seen as somber; comfortable shoes are best as you'll need to remove them before entering the Gurudwara.