This post really only applies to any of you who are attempting to build your alternate picking speed (or any speed I guess, whether economy, alternate, or sweep picking).
Anyway, for the last couple months I felt like I've been stuck at the same alternate picking speed, maybe increasing a couple bpm's every couple weeks or so. I was stuck at "kind of fast," but I want to eventually become "very fast."
So what I did was picked one part of a song I've been working on that was very difficult for me to play up to speed. Particularly this one part that has you playing triplets at 198 bpm across multiple strings. And it has a couple awkward positionings. I was only able to play these triplets at like 158 bpm. But what I did was just played this one part over and over like a couple hundred times every day. I would break it up into sections, play it all at once, play it at slow speeds, play it at speeds that were a little too fast, Basically I attacked it from all angles. After a couple months, this became pretty tedious and boring! But I forced myself to stick with it, slowly increasing the metronome when I felt comfortable.
And I'm happy to report, this approach works! I'm now at 190 bpm, only 8 more to go!
So my main message is this: doing this may seem very boring or even depressing at times. It may even seem pointless or like it's not working. And some days you may even be slower than you were the day before! (this is normal and it happened to me. I think because your hand gets fatigued some days) But sticking with it WILL pay off. Just keep telling yourself that it's IMPOSSIBLE not to get faster if you keep practicing the same things every day.
Also make sure to slow down enough so you can really make sure you're moving your fingers in the most efficient manner possible. Form is actually important here. Going really slow may seem like a waste of time, but for me I think that was one of the things that paid off the most.