For many players, including myself, one of the most persistent mechanical challenges is picking from one string to another. Of course, this can mean a wide variety of combinations, but let’s start with the most basic idea of getting your picking hand from one string to an adjacent string, using standard alternate picking. When learning or refining any technique, it’s important to isolate the motion to its most basic mechanical fundamentals, and build on it.
Let’s take the middle string pair, 3rd (G) and 4th (D) strings, and break down the mechanical motion of going from one string to the other. Imagine a point halfway between those two strings. If you start on the D string with a downstroke, and then play the G string with an upstroke, then you’re going from the “outside” of the strings toward that imaginary point; if you start on the G string with a downstroke followed by an upstroke on the D string, then you’re starting from the “inside” of the strings, heading “out” away from that midpoint. So for the sake of simplicity and common terminology, we’ll just refer to those as “outside” and “inside” picking combinations, respectively. See the tab below:
(*Note: Different players and teachers have different names for concepts such as this. I’ve seen other teachers and books refer to the “outside” one as “inside”, and vice versa. That’s fine; especially when it comes to naming things, the only rule is “whatever works”. If it makes more sense to you to call them “inside” and “outside”, “A” and “B”, or “Sid” and “Nancy”, then go for it. We’ll stick with “outside” and “inside” here just for the sake of having a common terminology.)
Try it out on all five adjacent string pairs briefly. It shouldn’t take long for it to sound fairly tedious, and more like an exercise than like actual music, so let’s come up with something. Here’s a quick progression to run through on the 3-4 string pair, that sounds more musical:
Since we’re just working with two-note figures (diads), the tonalities indicated above are just the most obvious ones within the key of A minor. For example, the first diad of A-C could also be a C6 inversion.
Fret-hand fingering should be pretty self-evident throughout; the final A-D diad can be either barred or played to set up the ending power chord. Mainly we want to focus on how the picking hand is situated throughout, maintaining a steady back-and-forth. Start with down-up picking at first, then try up-down. Also try reversing the note sequence for the diads with each picking configuration; for example, the first A-C diad would be C-A, exact same fingering, just different order.
Diads are pretty easy to develop and move around, so be sure to try out your own ideas, on as many adjacent string pairs as possible. The minor third interval tuning of the 2-3 (B-G) string pair should present some useful fingering ideas. These ideas apply to non-adjacent string groups as well, of course, but stick to adjacent string pairs until you feel like you have mastered these sequences, and you can play them smoothly and cleanly at a minimum of 120 bpm straight 16th notes. Again, focus on economizing the motion in your picking hand before bumping up your metronome.
Finally, here’s a fun and musical alternative to our diad sequence — since the overall key is Am, working in the open A string builds on the mechanical concept. Work both ideas on other string groups, further up the neck, etc.