My belief is that one of the best ways to quickly improve your improvisation is to focus on true mastery of all of your diatonic arpeggios, with an understanding of the relationships between them.
Why This Works
This method works well because it focuses on the ability of your fingers to instantly recognize different chord variations within a key.
Given a diatonic tone center, you can simplify your improvisation to play simple a combination of arpeggios within your key-center.
For example, using the classic ii-V-I progression. If you’re in the key of Eflat, a basic approximation of the chords would be to focus only on the execution of the Eflat tonality.
As a second step, then, you could begin to focus on the individual chords, but the ability of your hands to easily “catch” the Eflat major will inevitably underly your ability to transfer between each individual chord within the key.
How To Practice Diatonic Arpeggios for Jazz Improvisation
Mastery of your arpeggios, is akin to mastering the tonal center and physical feel of a key.
That means that playing arpeggios is simply a variation of your scale practice. I encourage you to practice the following sequences, with example sequences are given in the key of C major:
“Skipped 2nd” Scales: C-E-D-F-E-G-F-A-G, etc
Diatonic triads moving up the scale: C-E-G, D-F-A, E-G-B, etc
Diatonic triads moving down the scale: C-A-F, B-G-E, A-F-D, etc
Diatonic 7th chords moving up the scale: C-E-G-B, D-F-A-C, E-G-B-D, etc
Diatonic 7th chords moving down the scale: C-A-F-D, B-G-E-C, A-F-D-B, etc
Quartal Scale: C-F-D-G-E-A-F-B-G-C, etc
Practice each of these in both hands, for multiple octaves.
As you practice, don’t always start your practice on the root of each key. Move up and down the scale at will, constantly varying when and where you change the direction of each exercise.
After you can play each exercise easily in every key, practice mixing the exercises. For example, you might play 2 beats of diatonic 7th chords moving up the scale, following by a descending quartile scale for 2 beats.
This variation will begin to make your scale practice more like improvisation, and when it comes time to apply it to a song, you will have the necessary preparation behind you!