Brian’s drills are a good start.
Here is a video that explains cadence and its application
http://www.helmingathletics.com/2013/07/15/beat-fatigue-with-cadence-and-improve-your-run-transitions/
Another aspect to concentrate on is pulling your heel to your butt.
Think of your heel being on a track and pulling your heel to your butt.
http://www.youtube.com/watch?v=0rmaJV91Ayg
For
the metronome your can order one online or there are several apps if
you are comfortable running with your phone. Hearing the tempo will help
pull it all together.