Even though I like a mixture of furniture styles, I'm having trouble producing an informally elegant atmosphere in my large living room. Can you give me some general guidance?
I suggest that you keep things simple both in color and line. The floor, walls and curtains could all be done in shades of bleached linen, while at least some of the furniture might be in a similar color. The type of furnishings -- rustic, traditional or modern -- is less important than their color, which should not be dark.
You can't go wrong with high-quality wicker or rattan, especially if you intersperse these pieces with a few funky antiques.
This photo presents an example of the atmosphere I think you're trying to establish. Here, a bleached wood floor and putty-colored walls with white painted woodwork form a surround that comfortably accommodates a mixture of styles.
Just look at the seeming jumble of elements: a trestle-like birch log table with a glass top; a velvet-covered Jacobean high-back chair; a teak-armed sofa topped with squishy, multicolored silk cushions. Black iron antique furniture is also scattered throughout.
The deep-piled carpet is instrumental in making this setting look cleverly eclectic rather than merely chaotic. This particular floor covering comes from Tufenkian Tibetan Carpets of New York City. Its strong geometric patterns and neutral earth tones act as a steady base for the entire room.
Don't think that art and accessories are incidental just because I mention them last. Such details are essential to the casually elegant look that you're seeking. Some well-chosen pieces of folk art will make a great deal of difference to your living room's ultimate appearance.