Use a metronome and start slow, relax, and no tension. Am I missing something? For some reason I never manage to learn fast solos and sweeps. Are tips for building speed?
Building speed is the easiest thing to accomplish on guitar. It basically comes naturally. Everything else takes work.
I can sort of agree with what Ricky is saying. Speed will come with time. Speed comes with accuracy, and accuracy generally improves with time
What Vayne and Ricky said is very true. The people who ask how to build speed often have a few things in common, the most likely things are that they:

1. Put speed before accuracy and relaxation in their playing. You should never have speed as a goal, it is one of those things that comes naturally if you dont think about it.

2. Patience. They practice something slowly for a couple of days and then they get frustrated that they can´t play it much faster by then. Just like in everything else, dedication and patiences are the key to reward.
Fusion and jazz musician, a fan of most music.

Quote by Guthrie Govan
“If you steal from one person it's theft, and if you steal from lots of people it's research”

Quote by Chick Corea
"Only play what you hear. If you don't hear anything, don't play anything."