Her style is definetly coveted in the fashion world, and she has appeared several times in magizines such as Teen Vogue.
To get your own Agyness Deyn look here is what you need:
1. Bright color jeans: I really like them from Old Navy, I have 2 pairs: 1 in blue, and 1 in purple. Even though I am really short, the look OK rolled under (NOT CUFFED!)
2. Cartoon Charcter Tees OR Tees with chunky letters on them. ACTUALLY Teen Vogue has a tutorial on how to make your own! Here's the link: http://www.teenvogue.com/style/tips/diy/2007/05/henryholland_20070521
3. Canvas shoes. Converse, Vans,whatever floats your boat!
4. Like Agyness, always remember to have your own style, not a knock-off of someone else's.