A fundamental jazz improvisation skill is the ability to hear, think, see, and play the upper and lower neighbor tones for the primary chord tones in a major triad…
Upper and Lower Neighbor Tones, Straight Quarter Notes…
Notice that the upper neighbor tone is diatonic while the lower neighbor tone (a minor 2nd) may or may not be diatonic (Hint: if not diatonic you will see an accidental). As such the lower neighbor acts like a leading tone which provides stronger voice leading.
Upper and Lower Neighbor Tones, Swing 8th Notes…
Homework
As always, study and practice the patterns above in all keys you want to play in–using all four musical intelligences: ears, intellect (theory), eyes, and muscles! (With a rhythm track and always recording yourself, too!!!)