FOURTHS: A Practical Guide to Improvisation
This book attempts to present a simple introduction to 'Fourths'.
The more you play consecutive 'Fourths' clusters the more you get away from the sound produced by playing thirds, scales and arpeggios. But you can control that overall tonality by playing more or fewer 'Fourths', and by reverting back to the more 'conventional' techniques where and when melodic inspiration demands.
Put simply, slot in some 'Fourths' here and there to break up your usual improvs.