I've been playing guitar for almost 4 years now, but the only training or practice I have ever had is looking up songs, and learning the parts that make me "jam". I've never practice scales, nor have I learned chords or anything like that.

In order to progress in my music composition, I'm wondering what I should start learning. I know there's a method as to why songs sound good, and why certain chords are used (and even keys that the songs are in) but I have no idea about any of that.

Would this be part of musical theory? Basically, I want to learn scales and chords (though I don't know where to start) and I want to know how and why certain songs are made up like they are, and why they sound appealing like that.

I'm having a very hard time expressing my request (and English is my only language =P) but perhaps one of you may know what I'm trying to convey?

Would this also help me learn songs by ear? I have such a hard time with many of the more underground metal bands because they diverge from simple power chords and I can't discern what exactly is being played under all of the distortion.
Last edited by Corrosive at Aug 23, 2011,
i'm just posting because i'm in the same position as you but only been playing for about a year and a half and i wanna know the same thing
Some good basics on music theory will really help you.

"Ear Training" by Keith Wyatt will teach you a lot of theory in the context of teaching you how to hear it. It's a great book but it assumes that you know how to play a few scales on your guitar. It might be what you're for, although you may need some basic primers on scale patterns first.
a good ear is really important in all aspects of music. But some theoretical knowledge is needed to get the most benefit from ear training.
So learning both together at the same pace might be an ideal way for you to practice.