During cold weather months, opt for a quarter-length coat in place of a bulky sweater. A long coat gives you a streamlined, polished effect and can work with day or evening wear, perfect for stylish plus-sizes.
Make sure the structure of the coat isn't too boxy, because that will only make you look wider than you really are. Look for a coat that drapes softly over your curves and gives you a nice, smooth silhouette. Don't go with too-big or too-small buttons that distract from the overall design of the coat --- a good, quality coat wouldn't need that anyway!
Stay away from numerous embellishments and go with classic colors of white, navy or black. This will allow you to mix and match with other staples in your wardrobe.