How Do You Get Hair Like Oliver Hudson?

I`m just curious how I might go about growing my hair out. Right now I have shorter sides than top but the sides and back are looking a bit shaggy. I am aiming to grow my hair like Oliver Hudson. I`m sorry, I don`t have a pic but he`s the guy from "My Guide To Becoming A Rock Star" and the coffee shop guy from "Dawson`s Creek". Anyway, how do I go about growing it? Should I let the top grow a bit more and keep the side neat until the top is a bit longer or should I just let it all grow out and then fix it like I want it when it`s all longer. Sorry for the long message, but any help would be great. Thanks.