If it's casual sophistication you're after, why not trade your jeans and t-shirt ensembles for a shirt dress? These button-front styles are like a longer but equally comfy version of your boyfriend's dress shirt. Worn with a wide belt over opaque tights or leggings, this is a great look for shopping, running errands, or even for the office, depending on the length. (Wearing a shirt as a dress, however, is a fashion don't.) Here are some looks to try at various price points.
Ya-Ya Shirt Dress, $215, available here.
AKA New York Shirt Dress, $364, available here.
Edward An Bryce Shirt Dress, $220, available here.
To see the rest,
Norma Kamali Everlast Oversize Shirt Dress, $195, available here.
Bebe Vested Striped Shirt Dress, $119, available here.
Forever 21 Belted Shirt Dress, $34.80, available here.