I don't know what kind of guitar you're playing, but there's all kinds of factors why it doesn't sound like the recording...the most obvious reason being..they wrote it and they've had plenty of time to play it. After time you'll find yourself getting better at it and it sounding smoother and smoother. There's other factors though as far as tones go. They may be playing through a tube amp, whereas you're playing a solid state...you may be playing a Squire, and they're playing a PRS...they may be using a chorus or a flange or delay effects. You'll never get it to sound EXACTLY like the artist, but why would you want to? If people want to hear it done exactly like the artist...they'll buy the CD. Just keep plugging away, make sure you're playing it clean before you're playing it faster and it will come together.