Circle of 5ths

The Circle of 5ths is nothing more than a term used to describe the 2-5 relationship between chords. D to G, C to F, F to Bb. This is very important for you to get a handle on. Many chord changes that you will find are related to this circle of 5ths in some way, and much of the reharmonization we do is related to it. The Jazz Theory book by Mark Levine talks about it in detail.

Using the circle of fifths is a great way to practice chord change patterns. Cm-F7, Bbm-Eb7, Abm-Db7, etc... Then, alter the chords in all the ways imaginable. Anything that sounds good to you, well, do it in 12 keys!