Watch the D half dim to G7 to Cmin online guitar lesson by Fareed Haque from Bebop Improv Survival Guide

This play along focuses on the ii-V-I in a minor key.

What makes minor keys beautiful, a bit more complex and sometimes confusing is the nature of the 6ths and 7ths. Whereas in a major key for the most part 6 and 7 are always the same ["A" and "B" in the key of "C"], in a minor key we can use b6 or nat 6 [ "Ab' or "A"], b7 or nat 7 ["Bb" or "B"] to build chords and melodies.

So on a D 1/2 diminished chord you will definitely use an "Ab" in both chord and melody, on G7 you will definitely use a "B' as then 3rd of G7, and on Cm...well you can use either 6 or 7, flat or natural! The more you get to know the sounds thru playing and listening, the more you will find the ones you like, and the ones other jazz players have gravitated to in their explorations.