The best method is to practice at a slower tempo. Using a metronome, practice it as a pace where you can do it cleanly. Gradually increase the tempo until you can't play it cleanly any more. Back the tempo down slightly from there and practice.

You will find that from day to day, you will be able to increase the tempo more and more. By using a metronome to do this, you can measure your progress so you can see how you are improving.

I go through this myself all of the time and this method works.