Your in luck...on a terrace you will still have access to electricity. Stringing white lights is a great idea...for another choice try huricanne lanterns, a lighted waterfountain(you can rent these) or tikki torches(they make some really nice ones now, but don't used citronella...unless of course you need it) Buy a large plant or small tree...decorate with flowers to match your wedding, white lights, maybe a little tulle...instant specimen.