The Olsen twins truly know how to dress for themselves; and they do it so well that you can't help but like everything they wear even when you feel unsure. You can view their fall 2012 collection here.
The first two looks are by zero + maria cornejo. I really like the soft fluorescent green cape (surprisingly!) against the soft grey clothes -I like soft colours.
The bottom, middle look is by Proenza Schouler for Fall 2012. I like the contrast of the white clothing against the heavy, black knee-high boots; and I think the bag feminises (if that's a word) the whole look.