The style I've termed "Kelly Casual" consists of a basic tailored shirt (commonly white) and fitted pants--be they dungarees, capris or cigarette pants--with an attractive yet casual shoe, like a penny loafer or plain flat. And of course all of the ladies have their hair nicely styled and are wearing natural makeup. Some of them have dressed themselves up with an added accessory such as a striped scarf.
Notice that all of these ladies look streamlined and elegant. I think tailoring and simplicity are two key words here. None of them are wearing overly elaborate garments--they're all very simple in terms of taste and cut. And they are fitted beautifully--not saggy or unbecomingly draped. These principles are very easy to carry over into modern everyday dressing. Even a T-shirt can look good if it is fitted properly. :)