People if I knew the answer then you'd be paying handsomely for the information. The answer lies in the nuance, the fact how ever effortless the look looks, there is hard work and thought that has come into play to create it. Who you look to for style inspiration is probably getting tip top access to clothes, hair and makeup - not to mention PTs and dermatologists. The 'look' is a complete package.
It doesn't matter if you are a heels or flats gal, the opportunity to move your casual look into a new sphere is here.
Personally, keep it clean and fresh when it comes to casual. If you wear a bright colour or a pattern then keep hair, make up and accessories unfussy. If you go plain jane with jeans and a top then you need to bling your eyes, hair, lips or accessories - obviously not all at ONCE!
The Daily Mail hated this SJP look at first but then went on to use it at least three more times in a positive manner! That is the thing with change it makes you react, look again and then embrace. I loved this look straightaway - it is casual and easy. It looks as if no effort has been made but the bright down coat with the restrained colour palette of the boots, printed jeans and jumper says this has been thought through. Note no jewellery, no make up, no up do. The emphasis here is on the garments and the main feature is the coat.
image: The Daily Mail
The more traditional casual look is epitomised by Olivia Palermo. This is the truly modern version of that Park Avenue Princess look of jeans, white shirt and jacket.
images: The Daily Mail
It helps that Olivia has a great male accessory in her boyfriend but truly the detail is in her hair tied back without a hit of being brushed, some subtle pearl earrings and then the neutral palette of clothes and a splash of red in the shoes.
These folks are the new casual style stakes. Trying times indeed!