I started with the black outfit first because it's the odd one, the only solid one. The other two are prints. One's long sleeve with bell sleeves, a bit boho. They are all off-the-shoulder dresses paired with flats. I think long, casual dresses look best with flats. One qualifier there, if the dress is very straight (bodycon) then a heel is called for. That's all a matter of proportion. You just have to keep a maxi look neat. You can't allow it to get sloppy, or you run the danger of looking like you are still in your nightdress and need to go home and get dressed.
My pet peeve revealed: I hope every woman reading this has a full-length mirror and uses it every time she gets dressed. You are a three dimensional being and the world is all around you seeing you from all sides. Please be sure to check all views before you leave the house. Do not be caught with a faux pas because you didn't look.