In the space of a week, Alexa Chung has done some serious services to denim while out and about in New York. Spotted wearing not one but three killer blue denim outfits, all with a polished NYC edge (those capri-length jeans? There are no words), we can't wait to see what kind of fashion eye candy she comes up with this week when she jets back to her native London for the launch of her book It, which you can get your hands on from Thursday

As you’ll be aware from studying the ASOS A/W'13 trend guide, blue denim is massive this season, so let’s take a closer look at how to do it faultlessly…