Hearing Chord Changes
The trick to successful improvising is training your ears to hear chord changes. It's easier than you think. I mentioned in the CHORD THEORY section about I-IV-V being the most common chord progression. We'll start there.
As a reminder, here are the primary triad chords of the diatonic scale:
C Major Triads
Here is a recording of the diatonic triads ascending in order from a low C triad to a high C triad: DIATONIC TRIADS.
Each chord is sounded twice.