Decorating doorways and window frames with sweet-smelling greenery encourages guests to venture into different rooms, improving a party's flow. White-pine garlands, which have long, soft needles and full boughs, can be conveniently shipped to you ($50 for 25 yards, Yankee Petaler, 518-822-1320). Hanging fresh evergreens is easy: Hammer in two small nails at the top corners of a doorway or window and drape the swags over them.