A: While I appreciate the idea of dressing up a plain button-down shirt, the expression "you can’t make a silk purse out of a sow’s ear" comes to mind.  A plain cotton button down shirt is a workhouse garment; it’s not really meant for dressing up for going out at night.

For casual wear, however, I recommend emphasizing the sleek simplicity of the shirt by pairing it with a dark rinse jean and a pair of heeled boots.  Layer on a great looking jacket to keep the look long, lean, and simple.  Bonus points for topping off the outfit with a long scarf, like Clemence Poesy (pictured, left).

To make a plain button down shirt a little more dressed up for daytime, here’s a few ideas for standout accessories:
Necklace: Layer on a bold necklace—or two, or three.  Don’t hold back.  The bigger and bolder, the better!
Scarf: It’s amazing how a scarf can turn a simple outfit into one that’s simply stunning.  Give your plain shirt some personality with a patterned scarf.
Belt: To jazz up a plain shirt, take your belt to the extremes.  Either wear a belt that’s wide or one that’s super narrow.  If you go for the narrow option, consider wearing a two or three belts for a very downtown cool look.
Necktie: Do as men do and don a necktie.  Wear it loosely knotted for a casual menswear-as-womenswear look.