Firstly, Megan is wearing a black Rebel Yell tank top and some Billabong trousers. I like the combination of the decorative top with the dark and subtly patterned trousers, as they compliment each other very well. She then topped off her look with a baggy hoodie, a pair of white Nike trainers (sneakers), a backpack and some gorgeous cheetah print sunglasses. I love Megan's outfit, and it's definitely my style, but this guide can be adapted to suit your own personal preferences.
Credit: Thanks to Megan-fox.net for the image.