Someone commented on my last column, "How to Learn and Retain Music Faster and Have a Deeper Understanding of What You Know," that rock guys never understand theory or ear training.
While that's not as true as it once was (thanks to all things prog-rock), it was true to some extent for a long time.
Practicing ear training can be very tedious and nowhere near as fun as cranking an amp to 11 — or stage diving. While I'm not going to tell you that if you don't develop your ears you'll never be a good guit-artist, I must say there's nothing cooler than hearing a song and being able to play along with it or even learn it by the time it's done.
So here are some fun ways to develop your ear as a guitarist.
When I was in high school, whoever didn't need tabs to learn a song was basically Mozart. Despite not having the innate talent those kids had, I eventually found out I could develop something similar. There are people with perfect pitch (people who know all the notes being played) and people with relative pitch (people who develop the ability to find the notes being played).
One advantage guitarists have against other instruments is that certain chord shapes sound unbelievably distinctive. The best example I can think of is sometimes when a player uses a capo on the first fret and is playing in the key of Ab, the player still refers to the chords as G, D, C, etc. A big reason for that is, despite the chords being different, the shapes sound like G, D, C, etc. Once you've played guitar a bit, you'll recognize the sound of these shapes and be able to associate them with actual notes.
Another fun way to develop your ear is to create an easy-medium-hard list of songs to learn by ear. It helps to find songs that are guitar-oriented. "Highway to Hell" by AC/DC or "Bright Lights" by Gary Clark Jr. are guitar-oriented and simple, while trying to make a guitar adaptation of Skrillex on your first try isn't recommended.
Even if you're only into metal, Lamb of God isn't a good "easy" band to start with; start with Black Sabbath, some NIN like "Wish," etc. Here are a few I'd recommend:
EASY: "Money Maker" by the Black Keys, "Sixteen Saltines" by Jack White, "In Bloom" by Nirvana, "Paris" by Grace Potter
MEDIUM: "Belief" by John Mayer, "Boulevard of Broken Dreams" by Green Day, "Under the Bridge" by RHCP, "Misery Business" by Paramore
HARD: "One of Us is the Killer" by Dillinger Escape Plan, "White Limo" by Foo Fighters, "Karma Police" by Radiohead
Making sure the songs are guitar-oriented keeps it fun and cements the guitar in your hands. Keep in mind this list is meant to be done over the course of a few weeks and is designed for someone who's just starting to work on his/her ears. As you advance your relative pitch, you should make each stage more difficult. Also, when having a hard time, sing what you're trying to learn.
Disclaimer: I get that this might seem like work while music is meant to be fun. Here's a better perspective: Basketball players just want to play, but it makes sense to shoot 1,000 free throws in practice before the big game so they play their best. Treat music and guitar the same way. It does take practice to work on your ear, but practice makes it easier to learn songs and play more, and it's always a thrill to play your best.