Brainstorming....
1) With slubby tee, slouchy bag, boyfriend jeans and booties.
2) With those black Gap skinny pants, over a denim shirt, collar popped. Not sure about footwear ... loafers?
3) With white collared top paired with colored jeans. Something unexpected, like yellow.
4) With patterned jeans or patterned skirt; mix patterns. Would look awesome over brocade bottoms, something with shine. Check out Jcrew for inspiration.
5) This would look nice with that Rachel Roy Tree print skirt. Add top in a splash of bright color underneath. Or a black turtleneck. Belt it.
6) I'd totally try this over my neon/hot pink pencil skirt, over my navy silk blouse. Cobalt booties. Snake skin bag.
7) You could also wear this buttoned up under a bright blazer. (I was just on some site that was saying mixing brights is on trend this fall). Dark wash denim. Scarf (pattern mix). Neutral booties/bag.
8) I'd try pairing with burgundy. I really like burgundy and cobalt together this year. Burgundy pencil skirt? Yes, this sweater and a pencil skirt may seem too classic, but if you get the colors right and on trend, why not?
9) How about wearing it open, over a sequin or sparkle top?
Cobalt is off the moment, so do put this back into circulation! I have a special place in my own heart for argyle. I'd very likely throw on a long strand of pearls... which may be a bit too classic... but I probably couldn't help myself. A layer of several long necklaces would be cool too.