Hey man, I think your voice sounds pretty good on that soundcloud demo, and I have to second some of the posts here (mostly, that emulating rock singers is basically one step removed from emulating gospel and blues singers). But as far as thickening your voice is concerned, there are a few things you can do. First, practice Low Larynx exercises daily (or even multiple times a day). Basically to do this, run up your comfortable pitch zone at a moderate volume but making your tone sound like Yogi Bear. Hold your finger over your larynx (adam's apple) to make sure you are keeping it as low as you can. It will 'remember' where to go naturally once you train it to, and this will keep your throat open and your voice resonant. Also, as you get higher, focus singing out the front of your face (often referred to as the mask, or middle, voice). DO THIS WITHOUT STRAINING. It will allow you to sing with the resonance of your chest and the pitch of your head, which will really thicken up the top end. The more you do this, the smoother your transitions along the pitch spectrum will be, and the more thick and resonant your voice will be overall. Most importantly, sing EVERY day for as much time as you can dedicate (1/2 hour to and hour is usually really good). It will keep your pitch correct, your voice resonant, and your vocal chords loose and relaxed. You have a good voice already, so you should start to hear big sounds coming out soon.