To get a quick fix now, try the jacket over white jeans with a neutral t-shirt or lightweight knit. (Even in August, we always keep a second layer handy — if your office is anything like ours, those air-conditioned summer days can get chilly.) Later into autumn, the go-to uniform is bare legs and pencil skirts, topped off with some boyish basics, like a classic sweater and two-tone flats. After the first frost, go all-out ladylike with a floral secretary blouse, spectator heels and bright tights. Et voilà — tweed has never looked so chic: Shop the Looks.