Putting it together:
The skirt's hem should just skim the bottom of the kneecap. To balance the longer length, pick a curve-hugging cut; woven fabrics will work well here.
Choose a top that's structured, slightly roomy through the body, and hits at the hip; short or three-quarter sleeves keep the proportions right.
For the most flattering look, definitely opt for heels. And since the feel of this outfit is so pared-down, go for simple, architectural jewelry, like a cuff and hoop earrings.