In this episode of Captain Fantastic Plays For You, we begin to discuss how to develop a melody. It begins with two chords: Dmi7 and BbMaj7.
In the video, we begin by creating a vamp between these two chords, one measure per chord. The convenient thing about using these two chords is that they share three notes...
 
Dmi7 has the notes D F A C
BbMaj7 has the notes Bb D F A
 
These two chords as they are voiced [or fingered] in the video are shown below
 

 
Over these two chords one can use, just to start with, the notes D F and A which are pictured below across the fingerboard up through the 15th fret. We choose these notes because both chords share them. You will not be able to sound bad if you stick to these pitches. So now, it's just a matter of how creative can you get with three notes. Sure, it's a finite set but there still are many possibilities to lay down something cool!
 

 
In the second solo, the melody gets developed a bit further, this time by taking a one octave D minor scale and infusing some chromaticism. Below is the scale that is used in the video. Note that the actual scale is in blue and the chromatically altered notes are penned in red
 

 
In the final example, we use a full two octave D harmonic minor scale to construct our melody. The pitches that are boxed in are there to show where the root notes [D] appear in the scale.
 

 
Now shred grasshoppers!