Sometimes I'll play sequences; repeating ideas that move downward with the harmony. BUT, it's sometimes more interesting to play a sequence that goes UP while the chords go DOWN, creating a kind of contrary motion.
Think about picking just one note per chord, and using that as the "main" note of a small, simple motif. You can start with almost any note in the chord/scale, and go from there:
C7: use, say, a D (the 9th); Bb7 use E (the #11); Ab7 use F (the 13th); Gb7 use Gb; E7 take your pick, F# (9), G (the #9)
C7 try a Bb; Bb7 use C (9th); Ab7 use D (#11); Gb7 use Eb (13th) or E (7th), etc.
Think about picking just one note per chord, and using that as the "main" note of a small, simple motif. You can start with almost any note in the chord/scale, and go from there:
C7: use, say, a D (the 9th); Bb7 use E (the #11); Ab7 use F (the 13th); Gb7 use Gb; E7 take your pick, F# (9), G (the #9)
C7 try a Bb; Bb7 use C (9th); Ab7 use D (#11); Gb7 use Eb (13th) or E (7th), etc.