I'm really focusing on building my speed now that I want to learn this Dream Theater song. That means many hours of boring exercises with a metronome. I already have a kink in my back.
All the advice I hear on building speed is the same: "Use a metronome. Start slow. Gradually increase the tempo." But I'm taking a slightly different approach.
My metronome is a computer program called YMetronome. It lets me change the tempo automatically, so I don't have to stop playing. I could have it increase by 1bpm every minute, for example. I've chosen to have it decrease the tempo as I practice a lick. That way, instead of pushing myself into playing faster than I can handle, it gets easier, and I can focus on maintaining the best form I can the entire time.
The particular lick I'm working on for this song consists of 4 beats of 16th note triplets. The original tempo is 112bpm. My playing breaks down at about 80bpm. I have a long way to go. My method is to start at a high tempo that I can still handle and decrease by 1bpm every 10 seconds. I keep playing until it's too slow to keep the beat, around 25bpm. Today I did this starting at 75bpm.
I pinned a chart on my wall with every whole number from 75 to 112, my target tempo. Along with all the mindless speed drills, I'll run the lick like this once or twice per day and cross them off as I go. If all goes well, I should be up to speed within a month.