I'd first discern what color the groom and his mates are wearing, then move away from that shade, but not so far removed that you become the life of the party. It's his day. Well, hers in terms of planning, dreaming and so on. I went to a wedding where the groom and his complement had on beautiful grey tuxes with tails and waistcoats and black patent leather shoes, topped off with a matching ascot type of tie that exuding a very Old World feel against the blinding white shirts. The groom also wore a matching tophat. Very classy. It was summer so I went with a basic blue suit, not linen because the wrinkles drive me batty, although I love the feel. A cream shirt and a subdued tie--pale yellow with thin blue stripes. No pocket square because it was the early 80's and, at the time and place--New Jersey, long drooping pocket gear was en vogue. And being 21 I wanted to show everyone up! I cannot recollect the shoes, but I'm certain they were black. I was aiming for elegance with a touch of casualness so as not to clash with the groom--who happened to be a great friend.