The key to playing fast, is playing REAL slow! If you are trying to learn a solo, or part, from a recording, learn and perfect a few notes at a time. This is part of the Effortless Mastery system. Many people (myself included) tend to learn something, not fully correct, and then play, and practice it that way-basically practicing mistakes!
By removing the mistakes,the slow practicer(real word?) will eventually win the speed!