It's good to be picky

"After years of practice, the young guitar player will eventually overcome kenetic disabilities and being to focus more and more upon what is being played as opposed to how it is played. In other words, the quality of the music is now the primary concern. With this in mind, the maturing guitarist will temporarily sedate his on-going urge to play lightning fast guitar licks and flashy feats of fingerboard gymnastics. Finally, the guitarist comes face to face with the nemesis of every budding musical artist, namely, improvising over chord changes." - Pat Martino

My own personal background is very much shred/extreme metal. I spent years honing my down picking rhythm chops (ala Metallica), my alternate picking rhythm chops (ala Slayer, Megadeth), my tremelo picking (ala surf), but at the end of the day I find that while it gives me speed and stamina, it doesn’t always give you absolute control when it comes to crossing string groups, and "inside" and "outside" picking. I tend to break down picking into the following basic skills:

1) Down picking rhythm chops
Here, every note is down picked. There's no alternate picking at all. You're going for a tight, even, aggressive sound. Think Master of Puppets, which to me is more or less the perfect exercise for this as you're down picking 8th notes at 220 bpm.. it's no pushover to make that sound tight!

2) Alternate picking rhythm chops on 1 string
Here's we're going for all out speed and aggression. Think Angel of Death/War Ensemble. The goal is to play clean and tight, and have the control to mute/stop playing when it's not needed.

3) Tremelo picking
Try playing Miserlou and it becomes instantly clear how hard it is to make it sound even, but more so to keep it tight and clean for such an extended period of time.

4) 3 note per string alternate picking
This is your typical 3 note per string scalar exercise. The challenge here is crossing strings. You typically play d-u-d on 1 string, then u-d-u on the next string. This is where the mechanical problem presents itself. There are two ways to cross strings.

Pick down on a lower string and up on a higher string. I call this "outside" picking, because you're picking on the "outside" of the two strings.

Pick up on a up on a higher string, and up on a lower string. I call this "inside" picking, because you're picking "between" 2 strings.

Each of these represents a different mechanical challenge to your hands, and you can craft little exercises that isolate this mechanical problem, and practice them to overcome it.

5) Sweep picking
I think of sweep picking as "raking" the pick up or down a set of strings, muting with your left hand as you go along. Typically this is used to play triad arpeggios, ala Malmsteen. Here, the mechanical problem presents itself in muting the strings as you go so they don't ring out and sound like a chord, but rather have even separation and definition, and sound like an arpeggio.

6) Economy picking
This is more of the Frank Gambale sort of thing.

If you play an odd number of notes, you can continue to move the pick in the same direction. For example, if you're playing an ascending 3-note per string scale, you'd play d-u-d, cross over to the higher string with a down string and continue the motion of d-u-d. So your picking hand would be doing:
d - u - d (cross string to higher string) d - u - d

This works in the opposite manner as well. If you are playing a descending scale, you start with u - d - u, so your picking hand would be doing:
u - d - u (cross to lower string) u - d- u

If you play an even number of notes, you will change the direction. If you are ascending, you will cross over to a lower string and descend. So your picking hand would be doing:
d - u - d - u (cross to lower string) u - d - u etc.

If you are descending, you will cross over to a higher string and then ascend. So your picking hand would be doing:
u - d - u - d (cross to higher string) d - u -d etc.

The best way to get your head wrapped around this is check out how Jimmy Bruno and Frank Gambale play, as this is central to their technique.

7) Strict alternate picking
This one speaks for itself. You never break the d-u pattern, even if you cross strings or skip strings.

8) String skipping
All the same consideration of (4), (6) and (7) apply here, except you throw in skipped strings. This requires practice on its own to overcome the mechanical challenge of not hitting stray notes as you cross strings.

Thus, we have deconstructed picking into discrete mechanical challenges. The goal is to combine them all, and be able to change on the fly. Practice them seperately until you're comfortable with each style of picking, and slowly put it together lick by lick. The best way to learn all these techniques quickly is to use a metronome. Don't pick long complicated exercises, but rather, pick an exercise that isolates each problem, and allows you to work on it. The more complicated the fretting hand parts are, the more difficult it will be for you focus on training your picking hand. As you feel yourself becoming more comfortable and confident with the different picking techniques, expand you exercises to combine both left/right hand co-ordination as well as switch up between all the different picking techniques. The metronome is your best friend, because it serves as both a benchmark for your progress, as well as keeping you playing at the threshold of your capability so you can push your boundaries.

Always remember to warm up and stretch. Playing fast on the guitar can be physically demanding, and if you're not careful, you can really hurt yourself! And remember... it's meant to be *fun*, so play things you enjoy, keep pushing your limits, and go for the gold. Michael Angelo sums it up best: No Boundaries.

PS: Don't forget rhythm, vibrato, expression, phrasing and tempo amidst all the technical jargon :p