14.46Turn an ordinary progression into a richer one

Basic:

C → Dm → G7 → C

Add diminished:

C → C♯°7 → Dm → G7 → C

Or:

C → C♯°7 → Dm → F♯°7 → G7 → C

Now you have chromatic bass:

C → C♯ → D

and later:

F → F♯ → G

Much richer.