For the fashion Savy GCers out there

[FuzzieAlum]

If the wedding's at a church, don't wear spaghetti straps (or cover them with a sweater and reveal it all at the reception).

Also, it's traditional not to wear white or black at a wedding, whether it's formal or not. (For women, at least - I mean most guy's suits are black.)

You can't go wrong with a simple, traditional sheath in a summery color!