This dress reminds me of Princess Katherine Middleton. She has such a way of showing off her waive figure without showing much at all. I don't resemble Kate, except for the fact that I too have brunette hair, but this dress reminds me of her style.
I bought this dress last spring from Anthropologie. The necklace is also from Anthro, but I found an Etsy site that makes some similar styles. They even include a single strand version of the accessory.
When accessorizing my outfits I like to have a POC (pop of color) and I try to remember the color wheel. Try styling your outfits with opposite colors, it's unexpected!