Watch the The Fragrance of Chords online guitar lesson by Steve Vai from Alien Guitar Secrets: Passion & Warfare
Now I'd like to talk a little bit about learning chords on the guitar. When learning them, the first thing I'd tell you to do is to go out and master every chord that there is. Go ahead. But start with the simple ones! Chords are made up of the same principles as scales, with two levels I'd encourage you to focus on when learning them.
The first level is the academic side, which is the music theory or explanation behind what the chords are. But what exactly is the academic side? Let's take a D chord. The fact that it's called a D chord is academic, also the fingering of it, that it's major because it contains the 1st, 3rd, and 5th of the D major scale, and what it's voicing is (and what a voicing actually is), are all part of the academic or music theory side of learning. All of this is fine and good, but what I really recommend when learning the D chord is to listen very carefully. All of those things may be a D chord, but you have to hear it to really get what a D chord is. I highly recommend that when you're learning your chords, you practice your ability to listen deeply, and more so than anything else you'll do on the instrument, because from it everything else comes. When you're listening, you're not thinking. I know that sounds like a paradox, but it's true. And you can prove this to yourself - when your full attention is in listening, you've found the sweet spot of every single great master of improvisation.
In that situation where you're just listening, you're not criticizing. You can find yourself in a jamming situation and your mind can be off in all sorts of bizarre tangents, like judging someone or thinking someone is better than you, or just being uncomfortable, all of which can cut right at the root of your ability to be a free flowing improviser. So, can you see when you are thinking or listening? They're two very different dimensions. It's like tasting, smelling, touching, or seeing. All of our senses actually bring us into the state of having our attention put on something, and then the thinking mind comes in and puts it together.
To go back to the instrument, in the process of learning music and chords, I highly recommend you take a moment and meditate on the sound of a chord. Take the time and listen very deeply to it. Let it ring out completely, following every note to the end. Invest your attention in the atmosphere and fragrance of the chord. Knowing this is much better than knowing what it's called. Me and my friend, back when we were teenagers, would sit across from each other with guitars and turn the lights out in the room, taking turns hitting chords with which the other would have to tell a story. Meaning, what does that chord sound like? What is the story of that chord? What is the fragrance of it? When you do this enough, your ears develop "eyes", so to speak, so you hear something and you immediately have a creative visualization or a space that you can play something that seems organic. This is a great way to write songs, and will be your best tool. A song is an expression of an idea or a thought, whether it's heartbreak, joyous, a fast car, etc. Whatever it is you'll do, go into that intention and you'll be able to put chords to the idea. If you try to go to a chord based only on your academic understanding, you'll be lost. Unless you're keeping to a theoretical chord progression where everything moves along as it should, but then there won't be any depth to the technique.
Learning chords is as simple as putting your hands down on the guitar and playing. If you like the chord you hit, write it down! I used to fill books with cool chords I liked. Move around one note at a time, with your ear telling you where to go, not your sense of music theory. I'll also add that if you like music theory because it works and it sounds good, that's fine too! But there's nothing sweeter than hearing something in your inner ear and then just doing it; having it just come out. Understanding the quality of a chord and not just its technical aspect, to use an analogy, is like being an expert on honey - you can write books, study, break down its molecular structure, get a PhD in honey, be the world's leading expert on honey, but you'll never actually know honey until you taste it. It's experiential, not intellectual.